CVE-2026-67350: s9y Serendipity

Medium severity, CVSS 4.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Serendipity before 2.6.1 contains an open redirect vulnerability in exit.php that allows unauthenticated attackers to redirect users to arbitrary external sites by supplying a malicious Base64-encoded url parameter when the Track Exits plugin is configured with commentredirection set to s9y. Attackers can craft trusted-looking URLs leveraging the legitimate blog domain to conduct phishing, deliver malware, or bypass URL reputation filters.

Affected products

• s9y Serendipity: before 2.6.1 (fixed in 2.6.1)

Published 2026-07-31. Last modified 2026-09-09.