# CVE-2011-4957: Denial of service in n/a

> Remote attackers can crash WordPress by submitting comments with crafted URLs that trigger excessive recursive calls in the URL formatting function.

- **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:** 27 Jun 2012
- **Updated:** 17 Sep 2024
- **Also known as:** DEBIAN-CVE-2011-4957, GHSA-mf9x-p929-vr83

## What is CVE-2011-4957?

CVE-2011-4957 is a medium-severity denial of service vulnerability in Wordpress Wordpress, published on 27 Jun 2012. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The make_clickable function in wp-includes/formatting.php in WordPress before 3.1.1 does not properly check URLs before passing them to the PCRE library, which allows remote attackers to cause a denial of service (crash) via a comment with a crafted URL that triggers many recursive calls.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2011-4957?

It affects 1 product.


Products: Wordpress Wordpress.

## How do I fix CVE-2011-4957?

Upgrade to a fixed version.

## Is CVE-2011-4957 being exploited?

There is no known exploitation of CVE-2011-4957 in the wild and no public exploit code.

## Other vulnerabilities in Wordpress Wordpress

- [CVE-2026-63030](https://insights.sbomify.com/CVE-2026-63030/): WordPress Core Interpretation Conflict (critical 9.8, exploited in the wild)
- [CVE-2026-87902](https://insights.sbomify.com/CVE-2026-87902/): WordPress Core Remote File Inclusion (high 8.1, exploited in the wild)
- [CVE-2026-60137](https://insights.sbomify.com/CVE-2026-60137/): WordPress Core SQL Injection (medium 5.9, exploited in the wild)
- [CVE-2012-2399](https://insights.sbomify.com/CVE-2012-2399/): Cross-site scripting in n/a (critical 10.0)
- [CVE-2012-2400](https://insights.sbomify.com/CVE-2012-2400/): Other in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-4957 and fix it if it is affected.

What it is: CVE-2011-4957 is a medium-severity denial of service vulnerability in Wordpress Wordpress, published on 27 Jun 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-2011-4957 in the wild and no public exploit code.

Affected product: Wordpress Wordpress. 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-2011-4957/ (Markdown: https://insights.sbomify.com/CVE-2011-4957/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-4957
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-4957
- OSV: https://osv.dev/vulnerability/CVE-2011-4957

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-4957/
Summaries are generated and may contain mistakes; the official description above is the record.