# CVE-2025-66046: Memory corruption in libbiosig

> A stack-based buffer overflow in libbiosig allows arbitrary code execution via a crafted MFER file, affecting applications using this library.

- **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:** Yes
- **Published:** 11 Dec 2025
- **Updated:** 11 Dec 2025
- **Also known as:** DEBIAN-CVE-2025-66046, GHSA-273p-w65h-573c, UBUNTU-CVE-2025-66046

## What is CVE-2025-66046?

CVE-2025-66046 is a critical memory corruption vulnerability in The Biosig Project libbiosig, published on 11 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Several stack-based buffer overflow vulnerabilities exists in the MFER parsing functionality of The Biosig Project libbiosig 3.9.1. A specially crafted MFER file can lead to arbitrary code execution. An attacker can provide a malicious file to trigger these vulnerabilities.When Tag is 67

Weakness: CWE-787 (Out-of-bounds Write), CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2025-66046?

It affects 1 product.


Products: Libbiosig Project Libbiosig.

## How do I fix CVE-2025-66046?

Upgrade to a fixed version.

## Is CVE-2025-66046 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-66046 exists.

## Other vulnerabilities in The Biosig Project libbiosig

- [CVE-2026-22891](https://insights.sbomify.com/CVE-2026-22891/): Memory corruption in libbiosig (critical 9.8)
- [CVE-2025-66043](https://insights.sbomify.com/CVE-2025-66043/): Memory corruption in libbiosig (critical 9.8)
- [CVE-2025-66044](https://insights.sbomify.com/CVE-2025-66044/): Memory corruption in libbiosig (critical 9.8)
- [CVE-2025-66045](https://insights.sbomify.com/CVE-2025-66045/): Memory corruption in libbiosig (critical 9.8)
- [CVE-2025-66047](https://insights.sbomify.com/CVE-2025-66047/): Memory corruption in libbiosig (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-66046 and fix it if it is affected.

What it is: CVE-2025-66046 is a critical memory corruption vulnerability in The Biosig Project libbiosig, published on 11 Dec 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-2025-66046 exists.

Affected product: The Biosig Project libbiosig. 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-2025-66046/ (Markdown: https://insights.sbomify.com/CVE-2025-66046/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-66046
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-66046
- OSV: https://osv.dev/vulnerability/CVE-2025-66046

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-66046/
Summaries are generated and may contain mistakes; the official description above is the record.