TI-2026-37893 Aliases CVE-2026-52778 GHSA-px5m-h76g-p7p8

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

HIGH 82CWE-1333Published 2026-06-08 · Updated 2026-06-09

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service, Code execution
Confidentiality · integrity · availability: High · High · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-1333 and CWE-94.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00798 56th percentileScored 2026-11-07

Fix Fixed yeswiki (YesWiki): 4.6.6yeswiki/yeswiki (Packagist): 4.6.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
YesWiki	yeswiki	before 4.6.6	4.6.6	Patch available	CNA
—	yeswiki/yeswiki (Packagist)	before 4.6.6	4.6.6	Patch available	GHSA-px5m-h76g-p7p8

yeswiki VendorYesWiki Affected before 4.6.6 Fixed in 4.6.6 Patch available CNA
yeswiki/yeswiki (Packagist) Vendor— Affected before 4.6.6 Fixed in 4.6.6 Patch available GHSA-px5m-h76g-p7p8

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:yeswiki:yeswiki::::::::	—	—	YesWiki

cpe:2.3:a:yeswiki:yeswiki:*:*:*:*:*:*:*:* Versions — — ·YesWiki

Remediation

Fix · CNA yeswiki (YesWiki) Fixed in 4.6.6
Fix · GHSA-px5m-h76g-p7p8 yeswiki/yeswiki (Packagist) Fixed in 4.6.6 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-52778
2026-10-03 Alias added: GHSA-px5m-h76g-p7p8

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-52778

Other 4

TI-2026-34305 YesWiki: Unauthenticated SQL Injection CVSS 3.1CRITICAL 9.8
TI-2025-29089 YesWiki Vulnerable to Unauthenticated Site Backup Creation and Download CVSS 3.1CRITICAL 10.0
TI-2024-34399 Use of a Broken or Risky Cryptographic Algorithm in YesWiki CVSS 3.1CRITICAL 9.9
TI-2026-37882 YesWiki: Unauthenticated arbitrary page deletion via `{{erasespamedcomments}}` action CVSS 3.1CRITICAL 9.1
TI-2026-80227 SQL injection in YesWiki Bazar entry creation via date_maj_fiche CVSS 4.0HIGH 8.8
TI-2026-66114 YesWiki before 4.6.7 Missing Authorization via Attachment Download Handler CVSS 4.0HIGH 8.7

See all 85 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences