---
id: CVE-2026-104454
title: >-
  YesWiki before 4.6.7 contains an algorithmic-complexity denial of service in
  the wakka.php formatter due to an O(n^2) markdown-link regex
summary: >-
  YesWiki before 4.6.7 contains an algorithmic-complexity denial of service in
  the wakka.php formatter due to an O(n^2) markdown-link regex. Unauthenticated
  attackers can submit a small crafted body of bracket characters to the
  page-edit p…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-1333
vendor: YesWiki
product: yeswiki
affected:
  - yeswiki < 4.6.7
published: '2026-10-02'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T12:17:17.277'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-104454'
references:
  - url: 'https://github.com/YesWiki/yeswiki/security/advisories/GHSA-gf57-wg5m-h34q'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/yeswiki-before-4.6.7-redos-via-wakka-php-edit-preview-endpoint
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-02T12:17:44.341Z'
---

## Overview

YesWiki before 4.6.7 contains an algorithmic-complexity denial of service in the wakka.php formatter due to an O(n^2) markdown-link regex. Unauthenticated attackers can submit a small crafted body of bracket characters to the page-edit preview endpoint to pin PHP-FPM workers and saturate the pool.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.