Unsafe eval() execution in YesWiki Bazar CalcField.php
CVE-2026-52778 affects YesWiki, a PHP-based wiki system, in versions prior to 4.6.6. The vulnerability is in the Bazar form field calculator component, specifically CalcField.php, where user-supplied mathematical formulas are filtered using a complex recursive regular expression and then passed to PHP's eval() function. This design is unsafe for two reasons documented in the advisory: the recursive regex can be abused to trigger excessive backtracking or stack overflow conditions, causing Regular Expression Denial of Service, and the overall architecture relies on regex-based sanitization before eval(), so any bypass of that logic can directly result in arbitrary PHP code execution. The issue was fixed in YesWiki 4.6.6.
Are you exposed to this one?
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Recent activity
6 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.