p PatchFirst

CVE-2026-52778

CVE-2026-52778 · YesWiki has Unsafe eval() in Formula Calculator - Remote Code Execution (RCE) & Denial of Service (DoS)

This page contains facts from public vulnerability sources. Check the original advisory before updating.

YesWiki is a wiki system written in PHP. Prior to version 4.6.6, an unsafe execution vulnerability exists in the Bazar form field calculator (CalcField.php) of YesWiki. The application attempts to sanitize user-defined mathematical formulas using a complex recursive regular expression before passing them to the PHP eval() function. This implementation is inherently flawed: it is vulnerable to Regular Expression Denial of Service (ReDoS / Stack Overflow) which can crash the server, and it creates a high-risk architecture where any logic bypass directly results in arbitrary PHP code execution. Version 4.6.6 patches the issue.

CVSS 9.8 · Critical · EPSS 0.8% · Fix available

Published
Updated

Stack: php

Affected products and versions

  • yeswiki

    Versions
    • < 4.6.6: Affected

    No fix published

  • yeswiki/yeswiki Packagist

    Versions
    • 4.2.3
    • v4.1.0
    • v4.1.1
    • v4.1.2
    • v4.1.3
    • v4.1.4
    • v4.1.5
    • v4.2.0
    • v4.2.1
    • v4.2.2
    • v4.2.4
    • v4.3
    • v4.3.1
    • v4.4.0
    • v4.4.1
    • v4.4.2
    • v4.4.3
    • v4.4.4
    • v4.4.5
    • v4.5.0
    • v4.5.1
    • v4.5.2
    • v4.5.3
    • v4.5.4
    • v4.5.5
    • v4.6.0
    • v4.6.1
    • v4.6.2
    • v4.6.3
    • v4.6.4
    • v4.6.5
    Affected ranges
    • ECOSYSTEM: < 4.6.6

    Update to 4.6.6

Original sources

Check your server →