# CVE-2025-65501: Null dereference in n/a

> Remote attackers can cause a denial of service in libcoap via a crafted DTLS handshake triggering a null pointer dereference.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 24 Nov 2025
- **Updated:** 24 Nov 2025
- **Also known as:** DEBIAN-CVE-2025-65501, GHSA-cx3h-f553-x7gw, UBUNTU-CVE-2025-65501

## What is CVE-2025-65501?

CVE-2025-65501 is a medium-severity vulnerability in n/a, published on 24 Nov 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Null pointer dereference in coap_dtls_info_callback() in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a DTLS handshake where SSL_get_app_data() returns NULL.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2025-65501?

It affects 1 product.


Products: Libcoap Libcoap.

## How do I fix CVE-2025-65501?

Upgrade to a fixed version.

## Is CVE-2025-65501 being exploited?

There is no known exploitation of CVE-2025-65501 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2026-29013](https://insights.sbomify.com/CVE-2026-29013/): libcoap Out-of-Bounds Read in OSCORE CBOR Unwrap Handling (high 8.8)
- [CVE-2025-34468](https://insights.sbomify.com/CVE-2025-34468/): libcoap Stack-Based Buffer Overflow in Address Resolution DoS or Potential RCE (high 8.2)
- [CVE-2025-65493](https://insights.sbomify.com/CVE-2025-65493/): Null dereference in n/a (high 7.5)
- [CVE-2025-65494](https://insights.sbomify.com/CVE-2025-65494/): Null dereference in n/a (high 7.5)
- [CVE-2025-65495](https://insights.sbomify.com/CVE-2025-65495/): Integer overflow in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-65501 and fix it if it is affected.

What it is: CVE-2025-65501 is a medium-severity vulnerability in n/a, published on 24 Nov 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2025-65501 in the wild and no public exploit code.

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-2025-65501/ (Markdown: https://insights.sbomify.com/CVE-2025-65501/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-65501
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-65501
- OSV: https://osv.dev/vulnerability/CVE-2025-65501

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-65501/
Summaries are generated and may contain mistakes; the official description above is the record.