What it is
CVE-2024-39891 is an unauthenticated vulnerability affecting Twilio Authy. 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...
Vulnerability report
Exploited in the wild
Confirmed confidence
In CISA KEV
CVE-2024-39891
Authy
Twilio / Authy · affected before 26.1.0
- Severity
- CVSS 5.3 · Medium
- Confidence
- Confirmed
- Exploit status
- Exploited in the wild
- EPSS
- 1.7%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.
Who is affected?
Twilio / Authy affected before 26.1.0.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
Authy
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.)
Vendor
Product
Affected
Status
twilio
authy_2-factor_authentication
Before 26.1.0
Affected
twilio
authy_2-factor_authentication
Before 25.1.0
Affected
twilio
authy_2-factor_authentication
Before 26.1.0
Affected
twilio
authy_2-factor_authentication
Before 25.1.0
Affected
n/a
n/a
n/a
Affected
- Published
- 02 Jul 2024
- Exploitation Reported
- 23 Jul 2024
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- None
Tags
ios
android
cisa
CVE References
- CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2024-39891
- cwe.mitre.org/data/definitions/203.html cwe.mitre.org · CVE Record https://cwe.mitre.org/data/definitions/203.html
- twilio.com/docs/usage/security/reporting-vulnerabilities twilio.com · CVE Record https://www.twilio.com/docs/usage/security/reporting-vulnerabilities
- twilio.com/en-us/changelog twilio.com · CVE Record https://www.twilio.com/en-us/changelog
- bleepingcomputer.com/news/security/hackers-abused-api-to-verify-m... bleepingcomputer.com · CVE Record https://www.bleepingcomputer.com/news/security/hackers-abused-api-to-...
Exploitation evidence
Why KEV Intelligence marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
CISA
Independent exploitation attestation added to the KEV Intelligence record.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2024-07-23 00:00 UTC |
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- 0
- User-Agents
- 0
Raw values available in Pro and Enterprise.
Scanner coverage
No scanner integrations recorded yet.
Virtual patch status
No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Risk and context
Severity, weaknesses, and research context
CVSS v3.1
5.3
Medium
CVSS:3.1/AC:L/AV:N/A:N/C:L/I:N/PR:N/S:U/UI:N
EPSS
1.7%
Weaknesses
Timeline
From disclosure to observed exploitation
-
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
CVE published
Vulnerability disclosed publicly
-
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2024-39891
Free JSON includes basic KEV fields{
"cve_id": "CVE-2024-39891",
"confidence": "Confirmed",
"cvss_score": 5.3,
"cvss_estimated": false,
"epss_score": 0.01669,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}Early warning alerts
Get alerts on high-impact exploitation
Receive curator-selected alerts when exploitation activity warrants attention. Each alert includes the evidence and context needed to decide what requires attention now.