CVE DATABASE / CVE-2024-39891
CVE-2024-39891
Twilio Authy Information Disclosure Vulnerability
Confirmed exploited in the wild. Added 2024-07-23.
Federal remediation due 2024-08-13.
Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Summary
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.)
CVSS 3.1 breakdown
| Base score | 5.3 (MEDIUM) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| Attack vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | LOW |
| Integrity | NONE |
| Availability | NONE |
Weakness type (CWE)
Affected products
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References
- https://cwe.mitre.org/data/definitions/203.html
- https://www.bleepingcomputer.com/news/security/hackers-abused-api-to-verify-millions-of-authy-mfa-phone-numbers/
- https://www.twilio.com/docs/usage/security/reporting-vulnerabilities
- https://www.twilio.com/en-us/changelog
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-39891
Data: NIST NVD + CISA KEV. NVD last modified 2025-11-05. Always verify against the vendor advisory before acting.