Description
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.
References3
Metrics
- CVSS 3.1
-
4.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - CVSS 4.0
-
2.1
LOW
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 29 · as of 13 November 2026
- CWE
- CWE-601
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.