{"history":[{"alert":0,"cve":"CVE-2021-3493","id":22185,"kind":"epss","observed_at":1794500401,"payload":"{\"date\": \"2026-11-12\", \"epss\": 0.49166, \"percentile\": 0.98902}"},{"alert":0,"cve":"CVE-2021-3493","id":19804,"kind":"epss","observed_at":1794327601,"payload":"{\"date\": \"2026-11-10\", \"epss\": 0.49166, \"percentile\": 0.98894}"},{"alert":0,"cve":"CVE-2021-3493","id":17770,"kind":"epss","observed_at":1794241201,"payload":"{\"date\": \"2026-11-09\", \"epss\": 0.49166, \"percentile\": 0.98892}"},{"alert":0,"cve":"CVE-2021-3493","id":15834,"kind":"epss","observed_at":1794154800,"payload":"{\"date\": \"2026-11-08\", \"epss\": 0.49166, \"percentile\": 0.98892}"},{"alert":0,"cve":"CVE-2021-3493","id":13812,"kind":"epss","observed_at":1794068402,"payload":"{\"date\": \"2026-11-07\", \"epss\": 0.49166, \"percentile\": 0.98892}"},{"alert":0,"cve":"CVE-2021-3493","id":11594,"kind":"epss","observed_at":1793982001,"payload":"{\"date\": \"2026-11-06\", \"epss\": 0.49166, \"percentile\": 0.9889}"},{"alert":0,"cve":"CVE-2021-3493","id":9580,"kind":"epss","observed_at":1793938800,"payload":"{\"date\": \"2026-11-05\", \"epss\": 0.49166, \"percentile\": 0.98889}"},{"alert":1,"cve":"CVE-2021-3493","id":8432,"kind":"cna","observed_at":1793874000,"payload":"{\"containers\": {\"adp\": [{\"providerMetadata\": {\"dateUpdated\": \"2024-08-03T16:53:17.827Z\", \"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\"}, \"references\": [{\"tags\": [\"x_refsource_MISC\", \"x_transferred\"], \"url\": \"https://ubuntu.com/security/notices/USN-4917-1\"}, {\"tags\": [\"x_refsource_MISC\", \"x_transferred\"], \"url\": \"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52\"}, {\"tags\": [\"x_refsource_MISC\", \"x_transferred\"], \"url\": \"https://www.openwall.com/lists/oss-security/2021/04/16/1\"}, {\"tags\": [\"x_refsource_MISC\", \"x_transferred\"], \"url\": \"http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html\"}, {\"tags\": [\"x_refsource_MISC\", \"x_transferred\"], \"url\": \"http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html\"}, {\"tags\": [\"x_refsource_MISC\", \"x_transferred\"], \"url\": \"http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html\"}], \"title\": \"CVE Program Container\"}, {\"metrics\": [{\"other\": {\"content\": {\"id\": \"CVE-2021-3493\", \"options\": [{\"Exploitation\": \"active\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"role\": \"CISA Coordinator\", \"timestamp\": \"2025-02-07T12:30:18.913674Z\", \"version\": \"2.0.3\"}, \"type\": \"ssvc\"}}, {\"other\": {\"content\": {\"dateAdded\": \"2022-10-20\", \"reference\": \"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3493\"}, \"type\": \"kev\"}}], \"providerMetadata\": {\"dateUpdated\": \"2025-10-21T23:25:48.908Z\", \"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\"}, \"references\": [{\"tags\": [\"government-resource\"], \"url\": \"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3493\"}], \"timeline\": [{\"lang\": \"en\", \"time\": \"2022-10-20T00:00:00.000Z\", \"value\": \"CVE-2021-3493 added to CISA KEV\"}], \"title\": \"CISA ADP Vulnrichment\"}], \"cna\": {\"affected\": [{\"product\": \"linux kernel\", \"vendor\": \"Ubuntu\", \"versions\": [{\"lessThan\": \"5.8.0-50.56\", \"status\": \"affected\", \"version\": \"5.8 kernel\", \"versionType\": \"custom\"}, {\"lessThan\": \"5.4.0-72.80\", \"status\": \"affected\", \"version\": \"5.4 kernel\", \"versionType\": \"custom\"}, {\"lessThan\": \"4.15.0-142.146\", \"status\": \"affected\", \"version\": \"4.15 kernel\", \"versionType\": \"custom\"}, {\"lessThan\": \"4.4.0-209.241\", \"status\": \"affected\", \"version\": \"4.4 kernel\", \"versionType\": \"custom\"}]}], \"credits\": [{\"lang\": \"en\", \"value\": \"An independent security researcher reporting to the SSD Secure Disclosure program\"}], \"datePublic\": \"2021-04-15T00:00:00.000Z\", \"descriptions\": [{\"lang\": \"en\", \"value\": \"The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.\"}], \"metrics\": [{\"cvssV3_1\": {\"attackComplexity\": \"LOW\", \"attackVector\": \"LOCAL\", \"availabilityImpact\": \"HIGH\", \"baseScore\": 8.8, \"baseSeverity\": \"HIGH\", \"confidentialityImpact\": \"HIGH\", \"integrityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"scope\": \"CHANGED\", \"userInteraction\": \"NONE\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H\", \"version\": \"3.1\"}}], \"problemTypes\": [{\"descriptions\": [{\"cweId\": \"CWE-270\", \"description\": \"CWE-270: Privilege Context Switching Error\", \"lang\": \"en\", \"type\": \"CWE\"}]}], \"providerMetadata\": {\"dateUpdated\": \"2021-12-03T19:06:06.000Z\", \"orgId\": \"cc1ad9ee-3454-478d-9317-d3e869d708bc\", \"shortName\": \"canonical\"}, \"references\": [{\"tags\": [\"x_refsource_MISC\"], \"url\": \"https://ubuntu.com/security/notices/USN-4917-1\"}, {\"tags\": [\"x_refsource_MISC\"], \"url\": \"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52\"}, {\"tags\": [\"x_refsource_MISC\"], \"url\": \"https://www.openwall.com/lists/oss-security/2021/04/16/1\"}, {\"tags\": [\"x_refsource_MISC\"], \"url\": \"http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html\"}, {\"tags\": [\"x_refsource_MISC\"], \"url\": \"http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html\"}, {\"tags\": [\"x_refsource_MISC\"], \"url\": \"http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html\"}], \"solutions\": [{\"lang\": \"en\", \"value\": \"Apply https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52\"}], \"source\": {\"discovery\": \"EXTERNAL\"}, \"workarounds\": [{\"lang\": \"en\", \"value\": \"Disable unprivileged user namespaces.\"}], \"x_generator\": {\"engine\": \"Vulnogram 0.0.9\"}, \"x_legacyV4Record\": {\"CVE_data_meta\": {\"ASSIGNER\": \"security@ubuntu.com\", \"DATE_PUBLIC\": \"2021-04-15T00:00:00.000Z\", \"ID\": \"CVE-2021-3493\", \"STATE\": \"PUBLIC\"}, \"affects\": {\"vendor\": {\"vendor_data\": [{\"product\": {\"product_data\": [{\"product_name\": \"linux kernel\", \"version\": {\"version_data\": [{\"version_affected\": \"<\", \"version_name\": \"5.8 kernel\", \"version_value\": \"5.8.0-50.56\"}, {\"version_affected\": \"<\", \"version_name\": \"5.4 kernel\", \"version_value\": \"5.4.0-72.80\"}, {\"version_affected\": \"<\", \"version_name\": \"4.15 kernel\", \"version_value\": \"4.15.0-142.146\"}, {\"version_affected\": \"<\", \"version_name\": \"4.4 kernel\", \"version_value\": \"4.4.0-209.241\"}]}}]}, \"vendor_name\": \"Ubuntu\"}]}}, \"credit\": [{\"lang\": \"eng\", \"value\": \"An independent security researcher reporting to the SSD Secure Disclosure program\"}], \"data_format\": \"MITRE\", \"data_type\": \"CVE\", \"data_version\": \"4.0\", \"description\": {\"description_data\": [{\"lang\": \"eng\", \"value\": \"The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.\"}]}, \"generator\": {\"engine\": \"Vulnogram 0.0.9\"}, \"impact\": {\"cvss\": {\"attackComplexity\": \"LOW\", \"attackVector\": \"LOCAL\", \"availabilityImpact\": \"HIGH\", \"baseScore\": 8.8, \"baseSeverity\": \"HIGH\", \"confidentialityImpact\": \"HIGH\", \"integrityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"scope\": \"CHANGED\", \"userInteraction\": \"NONE\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H\", \"version\": \"3.1\"}}, \"problemtype\": {\"problemtype_data\": [{\"description\": [{\"lang\": \"eng\", \"value\": \"CWE-270: Privilege Context Switching Error\"}]}]}, \"references\": {\"reference_data\": [{\"name\": \"https://ubuntu.com/security/notices/USN-4917-1\", \"refsource\": \"MISC\", \"url\": \"https://ubuntu.com/security/notices/USN-4917-1\"}, {\"name\": \"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52\", \"refsource\": \"MISC\", \"url\": \"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52\"}, {\"name\": \"https://www.openwall.com/lists/oss-security/2021/04/16/1\", \"refsource\": \"MISC\", \"url\": \"https://www.openwall.com/lists/oss-security/2021/04/16/1\"}, {\"name\": \"http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html\", \"refsource\": \"MISC\", \"url\": \"http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html\"}, {\"name\": \"http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html\", \"refsource\": \"MISC\", \"url\": \"http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html\"}, {\"name\": \"http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html\", \"refsource\": \"MISC\", \"url\": \"http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html\"}]}, \"solution\": [{\"lang\": \"en\", \"value\": \"Apply https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52\"}], \"source\": {\"discovery\": \"EXTERNAL\"}, \"work_around\": [{\"lang\": \"en\", \"value\": \"Disable unprivileged user namespaces.\"}]}}}, \"cveMetadata\": {\"assignerOrgId\": \"cc1ad9ee-3454-478d-9317-d3e869d708bc\", \"assignerShortName\": \"canonical\", \"cveId\": \"CVE-2021-3493\", \"datePublished\": \"2021-04-17T04:20:16.706Z\", \"dateReserved\": \"2021-04-12T00:00:00.000Z\", \"dateUpdated\": \"2025-10-21T23:25:48.908Z\", \"state\": \"PUBLISHED\"}, \"dataType\": \"CVE_RECORD\", \"dataVersion\": \"5.1\"}"},{"alert":0,"cve":"CVE-2021-3493","id":7128,"kind":"epss","observed_at":1793809200,"payload":"{\"date\": \"2026-11-04\", \"epss\": 0.49166, \"percentile\": 0.98888}"},{"alert":0,"cve":"CVE-2021-3493","id":4905,"kind":"epss","observed_at":1793722800,"payload":"{\"date\": \"2026-11-03\", \"epss\": 0.49166, \"percentile\": 0.98886}"},{"alert":0,"cve":"CVE-2021-3493","id":2687,"kind":"epss","observed_at":1793665375,"payload":"{\"date\": \"2026-11-02\", \"epss\": 0.49166, \"percentile\": 0.98884}"},{"alert":1,"cve":"CVE-2021-3493","id":929,"kind":"kev","observed_at":1793665375,"payload":"{\"cveID\": \"CVE-2021-3493\", \"cwes\": [\"CWE-862\"], \"dateAdded\": \"2022-10-20\", \"dueDate\": \"2022-11-10\", \"forensicTriage\": \"No\", \"knownRansomwareCampaignUse\": \"Unknown\", \"notes\": \"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52; https://nvd.nist.gov/vuln/detail/CVE-2021-3493\", \"product\": \"Kernel\", \"requiredAction\": \"Apply updates per vendor instructions.\", \"shortDescription\": \"The overlayfs stacking file system in Linux kernel does not properly validate the application of file capabilities against user namespaces, which could lead to privilege escalation.\", \"vendorProject\": \"Linux\", \"vulnerabilityName\": \"Linux Kernel Privilege Escalation Vulnerability\"}"}],"record":{"affected":[{"product":"linux kernel","vendor":"Ubuntu","versions":[{"lessThan":"5.8.0-50.56","status":"affected","version":"5.8 kernel","versionType":"custom"},{"lessThan":"5.4.0-72.80","status":"affected","version":"5.4 kernel","versionType":"custom"},{"lessThan":"4.15.0-142.146","status":"affected","version":"4.15 kernel","versionType":"custom"},{"lessThan":"4.4.0-209.241","status":"affected","version":"4.4 kernel","versionType":"custom"}]}],"cna":{"containers":{"adp":[{"providerMetadata":{"dateUpdated":"2024-08-03T16:53:17.827Z","orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE"},"references":[{"tags":["x_refsource_MISC","x_transferred"],"url":"https://ubuntu.com/security/notices/USN-4917-1"},{"tags":["x_refsource_MISC","x_transferred"],"url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"},{"tags":["x_refsource_MISC","x_transferred"],"url":"https://www.openwall.com/lists/oss-security/2021/04/16/1"},{"tags":["x_refsource_MISC","x_transferred"],"url":"http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html"},{"tags":["x_refsource_MISC","x_transferred"],"url":"http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html"},{"tags":["x_refsource_MISC","x_transferred"],"url":"http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html"}],"title":"CVE Program Container"},{"metrics":[{"other":{"content":{"id":"CVE-2021-3493","options":[{"Exploitation":"active"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","timestamp":"2025-02-07T12:30:18.913674Z","version":"2.0.3"},"type":"ssvc"}},{"other":{"content":{"dateAdded":"2022-10-20","reference":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3493"},"type":"kev"}}],"providerMetadata":{"dateUpdated":"2025-10-21T23:25:48.908Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"references":[{"tags":["government-resource"],"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3493"}],"timeline":[{"lang":"en","time":"2022-10-20T00:00:00.000Z","value":"CVE-2021-3493 added to CISA KEV"}],"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"product":"linux kernel","vendor":"Ubuntu","versions":[{"lessThan":"5.8.0-50.56","status":"affected","version":"5.8 kernel","versionType":"custom"},{"lessThan":"5.4.0-72.80","status":"affected","version":"5.4 kernel","versionType":"custom"},{"lessThan":"4.15.0-142.146","status":"affected","version":"4.15 kernel","versionType":"custom"},{"lessThan":"4.4.0-209.241","status":"affected","version":"4.4 kernel","versionType":"custom"}]}],"credits":[{"lang":"en","value":"An independent security researcher reporting to the SSD Secure Disclosure program"}],"datePublic":"2021-04-15T00:00:00.000Z","descriptions":[{"lang":"en","value":"The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges."}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"LOCAL","availabilityImpact":"HIGH","baseScore":8.8,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-270","description":"CWE-270: Privilege Context Switching Error","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2021-12-03T19:06:06.000Z","orgId":"cc1ad9ee-3454-478d-9317-d3e869d708bc","shortName":"canonical"},"references":[{"tags":["x_refsource_MISC"],"url":"https://ubuntu.com/security/notices/USN-4917-1"},{"tags":["x_refsource_MISC"],"url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"},{"tags":["x_refsource_MISC"],"url":"https://www.openwall.com/lists/oss-security/2021/04/16/1"},{"tags":["x_refsource_MISC"],"url":"http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html"},{"tags":["x_refsource_MISC"],"url":"http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html"},{"tags":["x_refsource_MISC"],"url":"http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html"}],"solutions":[{"lang":"en","value":"Apply https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"}],"source":{"discovery":"EXTERNAL"},"workarounds":[{"lang":"en","value":"Disable unprivileged user namespaces."}],"x_generator":{"engine":"Vulnogram 0.0.9"},"x_legacyV4Record":{"CVE_data_meta":{"ASSIGNER":"security@ubuntu.com","DATE_PUBLIC":"2021-04-15T00:00:00.000Z","ID":"CVE-2021-3493","STATE":"PUBLIC"},"affects":{"vendor":{"vendor_data":[{"product":{"product_data":[{"product_name":"linux kernel","version":{"version_data":[{"version_affected":"<","version_name":"5.8 kernel","version_value":"5.8.0-50.56"},{"version_affected":"<","version_name":"5.4 kernel","version_value":"5.4.0-72.80"},{"version_affected":"<","version_name":"4.15 kernel","version_value":"4.15.0-142.146"},{"version_affected":"<","version_name":"4.4 kernel","version_value":"4.4.0-209.241"}]}}]},"vendor_name":"Ubuntu"}]}},"credit":[{"lang":"eng","value":"An independent security researcher reporting to the SSD Secure Disclosure program"}],"data_format":"MITRE","data_type":"CVE","data_version":"4.0","description":{"description_data":[{"lang":"eng","value":"The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges."}]},"generator":{"engine":"Vulnogram 0.0.9"},"impact":{"cvss":{"attackComplexity":"LOW","attackVector":"LOCAL","availabilityImpact":"HIGH","baseScore":8.8,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","version":"3.1"}},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"CWE-270: Privilege Context Switching Error"}]}]},"references":{"reference_data":[{"name":"https://ubuntu.com/security/notices/USN-4917-1","refsource":"MISC","url":"https://ubuntu.com/security/notices/USN-4917-1"},{"name":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52","refsource":"MISC","url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"},{"name":"https://www.openwall.com/lists/oss-security/2021/04/16/1","refsource":"MISC","url":"https://www.openwall.com/lists/oss-security/2021/04/16/1"},{"name":"http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html","refsource":"MISC","url":"http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html"},{"name":"http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html","refsource":"MISC","url":"http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html"},{"name":"http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html","refsource":"MISC","url":"http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html"}]},"solution":[{"lang":"en","value":"Apply https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"}],"source":{"discovery":"EXTERNAL"},"work_around":[{"lang":"en","value":"Disable unprivileged user namespaces."}]}}},"cveMetadata":{"assignerOrgId":"cc1ad9ee-3454-478d-9317-d3e869d708bc","assignerShortName":"canonical","cveId":"CVE-2021-3493","datePublished":"2021-04-17T04:20:16.706Z","dateReserved":"2021-04-12T00:00:00.000Z","dateUpdated":"2025-10-21T23:25:48.908Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.1"},"cna_checked":1794349204,"cve":"CVE-2021-3493","description":"The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.","epss":{"date":"2026-11-12","epss":0.49166,"percentile":0.98902},"epss_checked":1794522003,"first_seen":1793665375,"kev":{"cveID":"CVE-2021-3493","cwes":["CWE-862"],"dateAdded":"2022-10-20","dueDate":"2022-11-10","forensicTriage":"No","knownRansomwareCampaignUse":"Unknown","notes":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52; https://nvd.nist.gov/vuln/detail/CVE-2021-3493","product":"Kernel","requiredAction":"Apply updates per vendor instructions.","shortDescription":"The overlayfs stacking file system in Linux kernel does not properly validate the application of file capabilities against user namespaces, which could lead to privilege escalation.","vendorProject":"Linux","vulnerabilityName":"Linux Kernel Privilege Escalation Vulnerability"},"kev_checked":1794522003,"products":"Ubuntu linux kernel","references":["https://ubuntu.com/security/notices/USN-4917-1","https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52","https://www.openwall.com/lists/oss-security/2021/04/16/1","http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html","http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html","http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html","https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3493"],"score":{"attackComplexity":"LOW","attackVector":"LOCAL","availabilityImpact":"HIGH","baseScore":8.8,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","provider":"canonical","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","version":"3.1"},"solutions":"Apply https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52","state":"PUBLISHED","title":"Linux Kernel Privilege Escalation Vulnerability","updated_at":1794500401,"workarounds":"Disable unprivileged user namespaces."},"sources":[]}
