XSS in Cotonti
CVE-2026-100521
Cotonti through 1.0.0 contains a reflected cross-site scripting vulnerability in the search plugin highlight parameter that performs no HTML or JavaScript escaping. Attackers can craft malicious links with injected JavaScript in the highlight parameter that executes in the browser of any visitor who opens the link, including administrators.
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 (10.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 10.0% 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/plugins/search/search.header.php (technical-description)
- github.com/Cotonti/Cotonti/blob/1.0.0/plugins/search/search.page.first.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 search highlight parameter (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100521?
- CVE-2026-100521 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-2026-100521?
- Medium severity. CVSS v3 base score is 6.1 out of 10.