Exploitation evidence
Known exploited · CISA KEV listed
Added 2021-11-03. Ransomware campaign use: Known.
CISA required action: Apply updates per vendor instructions.
CISA due date: 2021-11-17. This is the catalog’s deadline, not an assessment of your organization’s exposure.
KEV checked 13 Nov 2026, 00:20 Jerusalem · Original catalog ↗Reported products and versions
SonicWall / Email Security
Default status: Not specified
- affected: 10.0.9 and earlier
Fixes and workarounds
No explicit solution text in the downloaded CVE record. Consult the vendor advisory; unaffected version ranges are shown above as reported, not inferred as a patch recommendation.
Sources and related reporting
Observed change timeline
History begins when Egret first downloads each source. It is not the complete upstream CVE history.
12 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-12",
"epss": 0.51689,
"percentile": 0.98963
}10 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-10",
"epss": 0.51689,
"percentile": 0.98956
}09 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-09",
"epss": 0.51689,
"percentile": 0.98955
}08 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-08",
"epss": 0.51689,
"percentile": 0.98954
}07 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-07",
"epss": 0.51689,
"percentile": 0.98953
}06 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-06",
"epss": 0.51689,
"percentile": 0.98953
}06 Nov 2026, 06:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-05",
"epss": 0.51689,
"percentile": 0.9895
}06 Nov 2026, 00:20 Jerusalem · CVE Program record changed
Stored CNA snapshot at this observation.
{
"containers": {
"adp": [
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"dateUpdated": "2024-08-03T17:30:07.261Z",
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],
"url": "https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0010"
}
],
"title": "CVE Program Container"
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{
"metrics": [
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"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 4.9,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "HIGH",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2021-20023",
"options": [
{
"Exploitation": "active"
},
{
"Automatable": "yes"
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{
"Technical Impact": "total"
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],
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"timestamp": "2026-08-12T03:55:24.717669Z",
"version": "2.0.3"
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{
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],
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}
],
"timeline": [
{
"lang": "en",
"time": "2021-11-03T00:00:00.000Z",
"value": "CVE-2021-20023 added to CISA KEV"
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],
"title": "CISA ADP Vulnrichment"
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],
"cna": {
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"vendor": "SonicWall",
"versions": [
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],
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{
"lang": "en",
"value": "SonicWall Email Security version 10.0.9.x contains a vulnerability that allows a post-authenticated attacker to read an arbitrary file on the remote host."
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-22",
"description": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')",
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"type": "CWE"
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}
],
"providerMetadata": {
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"orgId": "44b2ff79-1416-4492-88bb-ed0da00c7315",
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},
"references": [
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],
"url": "https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0010"
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],
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"ID": "CVE-2021-20023",
"STATE": "PUBLIC"
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"affects": {
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}
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},
"problemtype": {
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{
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"references": {
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},
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"assignerShortName": "sonicwall",
"cveId": "CVE-2021-20023",
"datePublished": "2021-04-20T11:55:13.000Z",
"dateReserved": "2020-12-17T00:00:00.000Z",
"dateUpdated": "2026-10-01T20:20:16.365Z",
"state": "PUBLISHED"
},
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}04 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-04",
"epss": 0.51689,
"percentile": 0.9895
}03 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-03",
"epss": 0.51689,
"percentile": 0.98949
}03 Nov 2026, 02:22 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-02",
"epss": 0.51689,
"percentile": 0.98947
}03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed
Stored KEV snapshot at this observation.
{
"cveID": "CVE-2021-20023",
"cwes": [
"CWE-22"
],
"dateAdded": "2021-11-03",
"dueDate": "2021-11-17",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Known",
"notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-20023",
"product": "SonicWall Email Security",
"requiredAction": "Apply updates per vendor instructions.",
"shortDescription": "SonicWall Email Security contains a path traversal vulnerability that allows a post-authenticated attacker to read files on the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20021 and CVE-2021-20022 to achieve privilege escalation.",
"vendorProject": "SonicWall",
"vulnerabilityName": "SonicWall Email Security Path Traversal Vulnerability"
}