# CVE-2025-7209: 9fans plan9port x509.c value_decode null pointer dereference

> A local attacker can cause a denial of service via null pointer dereference in the x509.c library component of Plan9port.

- **Severity:** Medium 4.8 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Jul 2025
- **Updated:** 9 Jul 2025
- **Also known as:** GHSA-v25m-v785-g666

## What is CVE-2025-7209?

CVE-2025-7209 is a medium-severity vulnerability in 9fans plan9port, published on 9 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-476 (NULL Pointer Dereference), CWE-404 (Improper Resource Shutdown or Release)

## Which versions are affected by CVE-2025-7209?

It affects 1 product.


Products: 9fans Plan9port.

## How do I fix CVE-2025-7209?

No fix has been published for CVE-2025-7209 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-7209 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-7209 exists.

## Other vulnerabilities in 9fans plan9port

- [CVE-2025-7208](https://insights.sbomify.com/CVE-2025-7208/): 9fans plan9port x509.c edump heap-based overflow (medium 5.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-7209 and fix it if it is affected.

What it is: CVE-2025-7209 is a medium-severity vulnerability in 9fans plan9port, published on 9 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-7209 exists.

Affected product: 9fans plan9port. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-7209/ (Markdown: https://insights.sbomify.com/CVE-2025-7209/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-7209
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-7209
- OSV: https://osv.dev/vulnerability/CVE-2025-7209

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-7209/
Summaries are generated and may contain mistakes; the official description above is the record.