XSS in Cotonti
CVE-2026-100522
Cotonti through 1.0.0 contains a reflected cross-site scripting vulnerability in message.php where the lng parameter is not properly escaped before output in the confirmation dialog. Unauthenticated attackers can craft malicious links with script payloads in the lng parameter to execute arbitrary JavaScript in victim browser sessions.
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: 0.002 (11.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 11.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/Cotonti/Cotonti (product)
- github.com/Cotonti/Cotonti/blob/1.0.0/message.php (technical-description)
- github.com/Cotonti/Cotonti/issues/1907 (issue-tracking)
- github.com/Cotonti/Cotonti/pull/1908 (issue-tracking, patch)
- VulnCheck Advisory: Cotonti through 1.0.0 Reflected XSS via message.php lng parameter (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100522?
- CVE-2026-100522 is a medium-severity vulnerability in Cotonti, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-09-26.
- How severe is CVE-2026-100522?
- Medium severity. CVSS v3 base score is 6.1 out of 10.