Open Redirect in Cotonti
CVE-2026-93869
Cotonti through 1.0.0 contains an open redirect vulnerability in the cot_url_check() function that validates redirect destinations using a regular expression lacking an end-of-string anchor. Attackers can bypass the redirect guard by supplying hostnames beginning with the site domain to redirect users to attacker-controlled hosts through the ratings plugin or other redirect callers.
Vulnerability class: Open Redirect
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: 0.004 (29.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 29.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/Cotonti/Cotonti/issues/1891 (issue-tracking)
- github.com/Cotonti/Cotonti/pull/1899 (issue-tracking, patch)
- github.com/Cotonti/Cotonti/blob/1.0.0/system/functions.php (technical-description)
- github.com/Cotonti/Cotonti/blob/1.0.0/plugins/ratings/ratings.ajax.php (technical-description)
- github.com/Cotonti/Cotonti (product)
- www.vulncheck.com/advisories/cotonti-through-1.0.0-open-redirect-via-unanchored… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-93869?
- CVE-2026-93869 is a medium-severity vulnerability in Cotonti, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2026-09-18.
- How severe is CVE-2026-93869?
- Medium severity. CVSS v3 base score is 6.1 out of 10.