CVE-2026-52778

Name of the Vulnerable Software and Affected Versions YesWiki versions prior to 4.6.6

Description An unsafe execution issue exists in the Bazar form field calculator within the CalcField.php file. The application uses a complex recursive regular expression to sanitize user-defined mathematical formulas before passing them to the PHP eval() function. This design is flawed and leads to two primary risks: Regular Expression Denial of Service (ReDoS), where deeply nested recursive patterns can cause a stack overflow and crash the server, and arbitrary PHP code execution if the regular expression validation is bypassed. The issue is specifically located in the formatValuesBeforeSave($entry) function. A logic bypass allows an attacker to execute native PHP commands, potentially leading to full host compromise, including the ability to read sensitive system files and modify application data.

Recommendations Update YesWiki to version 4.6.6. As a temporary mitigation, restrict access to the CalcField.php component or avoid using the Bazar form field calculator until the update is applied.