CVE-2026-52778

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 3.1

9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

0.8% chance of exploitation in the next 30 days; higher than 56% of CVEs (scores of 2026-10-25)

CWEs

CWE-94, CWE-1333

Published

2026-06-08

Modified

2026-10-06

Record from

the NVD, synced 2026-10-19

References

• https://github.com/YesWiki/yeswiki/commit/dd2bd8fb099de0d21504bda8a810693b3fcb8e52
• https://github.com/YesWiki/yeswiki/releases/tag/v4.6.6
• https://github.com/YesWiki/yeswiki/security/advisories/GHSA-px5m-h76g-p7p8
• https://github.com/YesWiki/yeswiki/security/advisories/GHSA-px5m-h76g-p7p8

Check your stackJSON