Exploitation evidence
Known exploited · CISA KEV listed
Added 2024-07-23. Ransomware campaign use: Unknown.
CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
CISA due date: 2024-08-13. 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
n/a / n/a
Default status: Not specified
- affected: n/a
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
CVE Program record ↗ · Download tracked evidence as JSON
- https://cwe.mitre.org/data/definitions/203.html
- https://www.twilio.com/docs/usage/security/reporting-vulnerabilities
- https://www.twilio.com/en-us/changelog
- https://www.bleepingcomputer.com/news/security/hackers-abused-api-to-verify-millions-of-authy-mfa-phone-numbers/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-39891
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": 0.01669,
"percentile": 0.77116
}10 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-10",
"epss": 0.01669,
"percentile": 0.76973
}09 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-09",
"epss": 0.01669,
"percentile": 0.76943
}08 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-08",
"epss": 0.01669,
"percentile": 0.76932
}07 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-07",
"epss": 0.01669,
"percentile": 0.76917
}06 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-06",
"epss": 0.01669,
"percentile": 0.76879
}06 Nov 2026, 06:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-05",
"epss": 0.01669,
"percentile": 0.76867
}04 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-04",
"epss": 0.01669,
"percentile": 0.7685
}04 Nov 2026, 00:20 Jerusalem · CVE Program record changed
Stored CNA snapshot at this observation.
{
"containers": {
"adp": [
{
"affected": [
{
"cpes": [
"cpe:2.3:a:twilio:authy_2-factor_authentication:*:*:*:*:*:*:*:*"
],
"defaultStatus": "unknown",
"product": "authy_2-factor_authentication",
"vendor": "twilio",
"versions": [
{
"lessThan": "26.1.0",
"status": "affected",
"version": "0",
"versionType": "custom"
},
{
"lessThan": "25.1.0",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
},
{
"cpes": [
"cpe:2.3:a:twilio:authy_2-factor_authentication:*:*:*:*:*:*:*:*"
],
"defaultStatus": "unknown",
"product": "authy_2-factor_authentication",
"vendor": "twilio",
"versions": [
{
"lessThan": "26.1.0",
"status": "affected",
"version": "0",
"versionType": "custom"
},
{
"lessThan": "25.1.0",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"metrics": [
{
"other": {
"content": {
"id": "CVE-2024-39891",
"options": [
{
"Exploitation": "active"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2024-07-23T03:55:42.678226Z",
"version": "2.0.3"
},
"type": "ssvc"
}
},
{
"other": {
"content": {
"dateAdded": "2024-07-23",
"reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-39891"
},
"type": "kev"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-203",
"description": "CWE-203 Observable Discrepancy",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2025-10-21T22:55:50.240Z",
"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-2024-39891"
}
],
"timeline": [
{
"lang": "en",
"time": "2024-07-23T00:00:00.000Z",
"value": "CVE-2024-39891 added to CISA KEV"
}
],
"title": "CISA ADP Vulnrichment"
},
{
"providerMetadata": {
"dateUpdated": "2024-08-02T04:33:11.402Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_transferred"
],
"url": "https://cwe.mitre.org/data/definitions/203.html"
},
{
"tags": [
"x_transferred"
],
"url": "https://www.twilio.com/docs/usage/security/reporting-vulnerabilities"
},
{
"tags": [
"x_transferred"
],
"url": "https://www.twilio.com/en-us/changelog"
},
{
"tags": [
"x_transferred"
],
"url": "https://www.bleepingcomputer.com/news/security/hackers-abused-api-to-verify-millions-of-authy-mfa-phone-numbers/"
}
],
"title": "CVE Program Container"
}
],
"cna": {
"affected": [
{
"product": "n/a",
"vendor": "n/a",
"versions": [
{
"status": "affected",
"version": "n/a"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Twilio Authy API, accessed by Authy Android before 25.1.0 and Authy iOS before 26.1.0, an unauthenticated endpoint provided access to certain phone-number data, as exploited in the wild in June 2024. Specifically, the endpoint accepted a stream of requests containing phone numbers, and responded with information about whether each phone number was registered with Authy. (Authy accounts were not compromised, however.)"
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AC:L/AV:N/A:N/C:L/I:N/PR:N/S:U/UI:N",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "n/a",
"lang": "en",
"type": "text"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2024-07-03T22:07:07.423Z",
"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
"shortName": "mitre"
},
"references": [
{
"url": "https://cwe.mitre.org/data/definitions/203.html"
},
{
"url": "https://www.twilio.com/docs/usage/security/reporting-vulnerabilities"
},
{
"url": "https://www.twilio.com/en-us/changelog"
},
{
"url": "https://www.bleepingcomputer.com/news/security/hackers-abused-api-to-verify-millions-of-authy-mfa-phone-numbers/"
}
]
}
},
"cveMetadata": {
"assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
"assignerShortName": "mitre",
"cveId": "CVE-2024-39891",
"datePublished": "2024-07-02T00:00:00.000Z",
"dateReserved": "2024-07-02T00:00:00.000Z",
"dateUpdated": "2025-10-21T22:55:50.240Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1"
}03 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-03",
"epss": 0.01669,
"percentile": 0.76807
}03 Nov 2026, 02:22 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-02",
"epss": 0.01669,
"percentile": 0.76779
}03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed
Stored KEV snapshot at this observation.
{
"cveID": "CVE-2024-39891",
"cwes": [
"CWE-203"
],
"dateAdded": "2024-07-23",
"dueDate": "2024-08-13",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Unknown",
"notes": "https://www.twilio.com/en-us/changelog/Security_Alert_Authy_App_Android_iOS; https://nvd.nist.gov/vuln/detail/CVE-2024-39891",
"product": "Authy",
"requiredAction": "Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.",
"shortDescription": "Twilio Authy contains an information disclosure vulnerability in its API that allows an unauthenticated endpoint to accept a request containing a phone number and respond with information about whether the phone number was registered with Authy.",
"vendorProject": "Twilio",
"vulnerabilityName": "Twilio Authy Information Disclosure Vulnerability"
}