WordPress wordpress core

WordPress Core <= 2.8.4 — Denial of Service

CVE-2009-3622Published Oct 20, 2009 · Updated Nov 13, 2026

Affected: ≤2.8.4Update to 2.8.5 or newer

All remediation steps

Watch core

Severity

Medium6.5

CVSS

6.5

CVSS 3.1 · CNA (Wordfence)

CVSS:3.1/AV:N/AC:L/PR:L/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:L Privileges required: Low
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

Unknown

Exploit prediction (EPSS)

No score

CISA KEV

Not listed

On this page7

Am I affected?

WordPress wordpress

Affected≤ 2.8.4
Patched in2.8.5

You are affected if you run ≤ 2.8.4. Version 2.8.5 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.

What to do

Update to version 2.8.5, 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.

Algorithmic complexity vulnerability in wp-trackback.php in WordPress before 2.8.5 allows remote attackers to cause a denial of service (CPU consumption and server hang) via a long title parameter in conjunction with a charset parameter composed of many comma-separated "UTF-8" substrings, related to the mb_convert_encoding function in PHP.

Exploits & references

Proof-of-concept & detection

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

Advisories & patches

Advisorywordfence.com

Timeline

Oct 20, 2009
CVE published
Severity medium, CVSS 6.5
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