XSS in Gestsup
CVE-2026-22198
GestSup versions prior to 3.2.60 contain a pre-authentication stored cross-site scripting (XSS) vulnerability in the API error logging functionality. By sending an API request with a crafted X-API-KEY header value (for example, to /api/v1/ticket.php), an unauthenticated attacker can cause attacker-controlled HTML/JavaScript to be written to log entries. When an administrator later views the affected logs in the web interface, the injected content is rendered without proper output encoding, resulting in arbitrary script execution in the administrator’s browser session.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (20.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000
Affected products
- Gestsup — versions 0
Weakness classification (CWE)
References
- gestsup.fr/index.php (release-notes, Release Notes)
- www.vulncheck.com/advisories/gestsup-stored-xss-in-api-error-logs (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-22198?
- CVE-2026-22198 is a medium-severity vulnerability in Gestsup, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-01-09.
- How severe is CVE-2026-22198?
- Medium severity. CVSS v3 base score is 6.1 out of 10.