# CVE-2013-6422: Security feature bypass in n/a

> Disabling peer verification in libcurl also disables host verification, allowing remote attackers to perform man-in-the-middle attacks via server spoofing.

- **Severity:** Medium 4.0 (`AV:N/AC:H/Au:N/C:P/I:P/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Dec 2013
- **Updated:** 6 Aug 2024
- **Also known as:** CURL-CVE-2013-6422, DEBIAN-CVE-2013-6422, DSA-2824-1, GHSA-fw5f-w62r-p5ww

## What is CVE-2013-6422?

CVE-2013-6422 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 23 Dec 2013. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The GnuTLS backend in libcurl 7.21.4 through 7.33.0, when disabling digital signature verification (CURLOPT_SSL_VERIFYPEER), also disables the CURLOPT_SSL_VERIFYHOST check for CN or SAN host name fields, which makes it easier for remote attackers to spoof servers and conduct man-in-the-middle (MITM) attacks.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2013-6422?

It affects 3 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, Haxx Libcurl.

## How do I fix CVE-2013-6422?

Upgrade to a fixed version.

## Is CVE-2013-6422 being exploited?

There is no known exploitation of CVE-2013-6422 in the wild and no public exploit code.

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2013-6422 and fix it if it is affected.

What it is: CVE-2013-6422 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 23 Dec 2013. 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-2013-6422 in the wild and no public exploit code.

Affected product: Canonical Ubuntu Linux. 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-2013-6422/ (Markdown: https://insights.sbomify.com/CVE-2013-6422/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2013-6422
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2013-6422
- OSV: https://osv.dev/vulnerability/CVE-2013-6422

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From sbomify Insights: https://insights.sbomify.com/CVE-2013-6422/
Summaries are generated and may contain mistakes; the official description above is the record.