# CVE-2012-4561: Denial of service in n/a

> Remote attackers can cause a denial of service via crash in libssh due to invalid pointer free on error paths.

- **Severity:** Medium 5.0 (`AV:N/AC:L/Au:N/C:N/I:N/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Nov 2012
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2012-4561, GHSA-m2v7-9rhw-324g

## What is CVE-2012-4561?

CVE-2012-4561 is a medium-severity denial of service vulnerability in n/a, published on 30 Nov 2012. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The (1) publickey_make_dss, (2) publickey_make_rsa, (3) signature_from_string, (4) ssh_do_sign, and (5) ssh_sign_session_id functions in keys.c in libssh before 0.5.3 free "an invalid pointer on an error path," which might allow remote attackers to cause a denial of service (crash) via unspecified vectors.

## Which versions are affected by CVE-2012-4561?

It affects 1 product.


Products: Libssh Libssh.

## How do I fix CVE-2012-4561?

Upgrade to a fixed version.

## Is CVE-2012-4561 being exploited?

There is no known exploitation of CVE-2012-4561 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2026-59851](https://insights.sbomify.com/CVE-2026-59851/): Libssh: libssh: authentication bypass via missing gssapi principal check (high 8.8)
- [CVE-2025-5987](https://insights.sbomify.com/CVE-2025-5987/): Libssh: invalid return code for chacha20 poly1305 with openssl backend (high 8.1)
- [CVE-2025-14821](https://insights.sbomify.com/CVE-2025-14821/): Libssh: libssh: insecure default configuration leads to local man-in-the-middle attacks on windows (high 7.8)
- [CVE-2012-4560](https://insights.sbomify.com/CVE-2012-4560/): Memory corruption in n/a (high 7.5)
- [CVE-2012-4562](https://insights.sbomify.com/CVE-2012-4562/): Integer overflow in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2012-4561 and fix it if it is affected.

What it is: CVE-2012-4561 is a medium-severity denial of service vulnerability in n/a, published on 30 Nov 2012. 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-2012-4561 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-2012-4561/ (Markdown: https://insights.sbomify.com/CVE-2012-4561/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2012-4561
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2012-4561
- OSV: https://osv.dev/vulnerability/CVE-2012-4561

---
From sbomify Insights: https://insights.sbomify.com/CVE-2012-4561/
Summaries are generated and may contain mistakes; the official description above is the record.