Cloudanix VulnDB

CVE-2026-52778

Critical · 9.8

CVSS

9.8

EPSS

0.8%

Published

Jun 8, 2026

CISA due date

—

The record

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.

Affected packages

Ecosystem Package Introduced Fixed

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