CVE-2025-62408: c-ares has a Use After Free vulnerability when connection is cleaned up after error

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-12-08 · updated 2026-10-14
Weakness: CWE-416

Description

c-ares is an asynchronous resolver library. Versions 1.32.3 through 1.34.5 terminate a query after maximum attempts when using read_answer() and process_answer(), which can cause a Denial of Service. This issue is fixed in version 1.34.6.

Affected products

c-ares: from 1.32.3 before 1.34.6 — fixed in 1.34.6

How to fix

Upgrade to a fixed version: c-ares 1.34.6. Check the vendor advisory for mitigations.

References

https://github.com/c-ares/c-ares/commit/714bf5675c541bd1e668a8db8e67ce012651e618
https://github.com/c-ares/c-ares/security/advisories/GHSA-jq53-42q6-pqr5

Get alerted when CVE-2025-62408 or the next vulnerability affects your stack