Vulnerability · Published Jun 8, 2026 · Assigned by GitHub_M

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

Critical 9.8

In plain English

A critical-severity code injection in yeswiki from YesWiki. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 57% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical

Exploit odds (30 days)0.8%top 43.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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 & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	yeswiki/yeswiki	4.6.6	GHSA-px5m-h76g-p7p8

Affected products (as reported)

Vendor	Product	Versions
YesWiki	yeswiki	< 4.6.6

Weakness: CWE-94, CWE-1333 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

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