# CVE-2011-4318: Security feature bypass in n/a

> Man-in-the-middle attackers can spoof SSL servers in Dovecot when using hostname-based proxying, bypassing certificate validation.

- **Severity:** Medium 5.8 (`AV:N/AC:M/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:** 7 Mar 2013
- **Updated:** 7 Aug 2024
- **Also known as:** DEBIAN-CVE-2011-4318, GHSA-w2rf-p589-jpp8

## What is CVE-2011-4318?

CVE-2011-4318 is a medium-severity vulnerability in Dovecot Dovecot, published on 7 Mar 2013. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Dovecot 2.0.x before 2.0.16, when ssl or starttls is enabled and hostname is used to define the proxy destination, does not verify that the server hostname matches a domain name in the subject's Common Name (CN) of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via a valid certificate for a different hostname.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2011-4318?

It affects 1 product.


Products: Dovecot Dovecot.

## How do I fix CVE-2011-4318?

Upgrade to a fixed version.

## Is CVE-2011-4318 being exploited?

There is no known exploitation of CVE-2011-4318 in the wild and no public exploit code.

## Other vulnerabilities in Dovecot Dovecot

- [CVE-2026-24031](https://insights.sbomify.com/CVE-2026-24031/): Auth bypass in OX Dovecot Pro (high 7.7)
- [CVE-2025-59032](https://insights.sbomify.com/CVE-2025-59032/): Denial of service in OX Dovecot Pro (high 7.5)
- [CVE-2026-27858](https://insights.sbomify.com/CVE-2026-27858/): Denial of service in OX Dovecot Pro (high 7.5)
- [CVE-2021-29157](https://insights.sbomify.com/CVE-2021-29157/): Path traversal in n/a (high 7.5)
- [CVE-2020-10957](https://insights.sbomify.com/CVE-2020-10957/): Null dereference in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-4318 and fix it if it is affected.

What it is: CVE-2011-4318 is a medium-severity vulnerability in Dovecot Dovecot, published on 7 Mar 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-2011-4318 in the wild and no public exploit code.

Affected product: Dovecot Dovecot. 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-2011-4318/ (Markdown: https://insights.sbomify.com/CVE-2011-4318/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-4318
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-4318
- OSV: https://osv.dev/vulnerability/CVE-2011-4318

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-4318/
Summaries are generated and may contain mistakes; the official description above is the record.