# CVE-2009-0127: Security feature bypass in n/a

> Remote attackers can bypass SSL/TLS certificate validation via malformed signatures due to unchecked return values in M2Crypto verification functions.

- **Severity:** Medium 5.0 (`AV:N/AC:L/Au:N/C:P/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Jan 2009
- **Updated:** 16 Sep 2024
- **Also known as:** DEBIAN-CVE-2009-0127, GHSA-933f-4fwg-646j

## What is CVE-2009-0127?

CVE-2009-0127 is a medium-severity vulnerability in n/a, published on 15 Jan 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

M2Crypto does not properly check the return value from the OpenSSL EVP_VerifyFinal, DSA_verify, ECDSA_verify, DSA_do_verify, and ECDSA_do_verify functions, which might allow remote attackers to bypass validation of the certificate chain via a malformed SSL/TLS signature, a similar vulnerability to CVE-2008-5077.  NOTE: a Linux vendor disputes the relevance of this report to the M2Crypto product because "these functions are not used anywhere in m2crypto.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2009-0127?

It affects 1 product.


Products: Heikkitoivonen M2crypto.

## How do I fix CVE-2009-0127?

No fix has been published for CVE-2009-0127 yet. Limit exposure of the affected software until one is available.

## Is CVE-2009-0127 being exploited?

There is no known exploitation of CVE-2009-0127 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2009-0127 and fix it if it is affected.

What it is: CVE-2009-0127 is a medium-severity vulnerability in n/a, published on 15 Jan 2009. 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-2009-0127 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-2009-0127/ (Markdown: https://insights.sbomify.com/CVE-2009-0127/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2009-0127
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2009-0127
- OSV: https://osv.dev/vulnerability/CVE-2009-0127

---
From sbomify Insights: https://insights.sbomify.com/CVE-2009-0127/
Summaries are generated and may contain mistakes; the official description above is the record.