---
cve: "CVE-2026-52778"
severity: "CRITICAL"
cvss: 9.8
epss: "0.6%"
vendor: "YesWiki"
kev: false
exploited: false
published: "2026-06-08 19:16:46"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-20T16:10:29+02:00"
---

# CVE-2026-52778

> 9.8 CRITICAL · 🧪 PoC

## Beschreibung

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-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- dd2bd8fb099de0d21504bda8a810693b3fcb8e52 (Commit)
- fa81922f4103630911cbea98ead3c4b7bc786e19 (Commit)

## Referenzen

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

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-52778) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_