CVE-2024-39891In 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 Jun…
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It affects twilio authy_2-factor_authentication and 2 other products. Add what you run to find out whether that includes you.
CISA lists it as known exploited since Jul 23, 2024; federal agencies had to remediate by Aug 13, 2024. Treat that date as your deadline.
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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
- 5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AC:L/AV:N/A:N/C:L/I:N/PR:N/S:U/UI:N
- Weakness (CWE)
- CWE-203
- Known exploited
- Added to CISA KEV Jul 23, 2024; federal remediation due Aug 13, 2024Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- EPSS (exploitation in the next 30 days)
- 1.67% (percentile 76)
- Assigned by
- mitre
- NVD analysis
- Analyzed
- Record last updated
- Oct 21, 2025
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
twilio authy_2-factor_authentication twilio:authy_2-factor_authentication | before 26.1.0; before 25.1.0 | CISA ADP |
twilio authy twilio:authy | before 26.1.0 | NVD |
twilio authy_authenticator twilio:authy_authenticator | before 25.1.0 | NVD |
References
- https://cwe.mitre.org/data/definitions/203.htmltechnical-description
- https://www.twilio.com/docs/usage/security/reporting-vulnerabilitiesproduct
- https://www.twilio.com/en-us/changelogrelease-notes
- https://www.bleepingcomputer.com/news/security/hackers-abused-api-to-verify-millions-of-authy-mfa-phone-numbers/press/media-coverage
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-39891us-government-resource
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.