# CVE-2025-65495: Integer overflow in n/a

> Remote attackers can cause denial of service in libcoap by sending a crafted TLS certificate that triggers an integer signedness error.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Nov 2025
- **Updated:** 24 Nov 2025
- **Also known as:** DEBIAN-CVE-2025-65495, GHSA-vr3h-29qc-jvjf, UBUNTU-CVE-2025-65495

## What is CVE-2025-65495?

CVE-2025-65495 is a high-severity vulnerability in n/a, published on 24 Nov 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Integer signedness error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted TLS certificate that causes i2d_X509() to return -1 and be misused as a malloc() size parameter.

Weakness: CWE-195 (Signed to Unsigned Conversion Error)

## Which versions are affected by CVE-2025-65495?

It affects 1 product.


Products: Libcoap Libcoap.

## How do I fix CVE-2025-65495?

Upgrade to a fixed version.

## Is CVE-2025-65495 being exploited?

There is no known exploitation of CVE-2025-65495 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-2023-30362](https://insights.sbomify.com/CVE-2023-30362/): Information disclosure in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-65495 and fix it if it is affected.

What it is: CVE-2025-65495 is a high-severity vulnerability in n/a, published on 24 Nov 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-65495 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-2025-65495/ (Markdown: https://insights.sbomify.com/CVE-2025-65495/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-65495
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-65495
- OSV: https://osv.dev/vulnerability/CVE-2025-65495

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-65495/
Summaries are generated and may contain mistakes; the official description above is the record.