WordPress wordpress core

WordPress Core < 3.1.1 — Denial of Service

CVE-2011-4957Published Apr 5, 2011 · Updated Nov 13, 2026

Affected: <3.1.1Update to 3.1.1 or newer

All remediation steps

Watch core

Severity

High7.5

CVSS

7.5

CVSS 3.1 · CNA (Wordfence)

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

What does this vector mean?

AV:N Attack vector: Network
AC:L Attack complexity: Low
PR:N Privileges required: None
UI:N User interaction: None
S:U Scope: Unchanged
C:N Confidentiality: None
I:N Integrity: None
A:H Availability: High

Weakness

CWE-400 Uncontrolled Resource Consumption

Required access

No account needed

Exploit prediction (EPSS)

No score

CISA KEV

Not listed

On this page7

Am I affected?

WordPress wordpress

Affected< 3.1.1
Patched in3.1.1

You are affected if you run < 3.1.1. Version 3.1.1 and later are not affected by this issue.

Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under WordPress.
No admin access? Run a passive check of your site. It reads public files only.
No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

Update to version 3.1.1, or a newer patched version
Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
Watch WordPress to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence.

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.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

Advisorywordfence.com

Timeline

Apr 5, 2011
CVE published
Severity high, CVSS 7.5
Nov 13, 2026
Record last updated

Sources & licenses

Wordfence record

Vulnerability data: Wordfence Intelligence. [object Object] Licensed under the CC BY-SA 4.0.
CVE® identifiers: [object Object]. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
CVSS / CWE: National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.

How we use these sources