pac4j-core before 6.5.6 contains an open redirect vulnerability in DefaultLogoutLogic.perform() that accepts backslash-prefixed logout redirect targets matching logoutUrlPattern. Attackers can craft logout links with backslash-prefixed external hosts that browsers normalize into network-path references, redirecting victims to attacker-controlled sites after logout.
https://www.vulncheck.com/advisories/pac4j-core-before-6.5.6-open-redirect-via-backslash-logout
https://www.pac4j.org/blog/security-advisory-pac4j-core-oidc-saml.html
https://github.com/pac4j/pac4j/commit/2270c3ff70e93cc43831e75702acd5135531237e
Published: 2026-08-29
Updated: 2026-08-29
Base Score: 6.4
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N
Severity: Medium
Base Score: 6.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Severity: Medium
Base Score: 5.3
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Severity: Medium