# CVE-2025-50518: Use after free in n/a

> A use-after-free in libcoap allows arbitrary code execution if the library is used incorrectly by the application.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Aug 2025
- **Updated:** 11 Sep 2025
- **Also known as:** GHSA-fc59-q736-3r9p, UBUNTU-CVE-2025-50518

## What is CVE-2025-50518?

CVE-2025-50518 is a critical use after free vulnerability in n/a, published on 14 Aug 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A use-after-free vulnerability exists in the coap_delete_pdu_lkd function within coap_pdu.c of the libcoap library. This issue occurs due to improper handling of memory after the freeing of a PDU object, leading to potential memory corruption or the possibility of executing arbitrary code. NOTE: this is disputed by the Supplier because it only occurs when an application uses libcoap incorrectly.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2025-50518?


## How do I fix CVE-2025-50518?

No fix has been published for CVE-2025-50518 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-50518 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-50518 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-50518 and fix it if it is affected.

What it is: CVE-2025-50518 is a critical use after free vulnerability in n/a, published on 14 Aug 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-50518 exists.

Affected product: n/a. 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-2025-50518/ (Markdown: https://insights.sbomify.com/CVE-2025-50518/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-50518
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-50518
- OSV: https://osv.dev/vulnerability/CVE-2025-50518

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-50518/
Summaries are generated and may contain mistakes; the official description above is the record.