Jenkins Open Redirect Through Newline/Tab Characters in Redirect URL

Jenkins 2.567 and earlier, LTS 2.555.2 and earlier improperly determines that a redirect URL after login is legitimately pointing to Jenkins when it contains tab or newline characters between //, allowing attackers to perform phishing attacks.

References

• https://nvd.nist.gov/vuln/detail/CVE-2026-53437

• https://www.jenkins.io/security/advisory/2026-06-10/#SECURITY-3711+3755

• https://access.redhat.com/security/cve/CVE-2026-53437

• https://bugzilla.redhat.com/show_bug.cgi?id=2487544

• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53437.json

• jenkinsci/jenkins@8ef5289

• jenkinsci/jenkins@b32f2f2

• https://access.redhat.com/errata/RHSA-2026:60259

• https://access.redhat.com/errata/RHSA-2026:60256

• https://access.redhat.com/errata/RHSA-2026:60254

• https://access.redhat.com/errata/RHSA-2026:60252

• https://access.redhat.com/errata/RHSA-2026:60251

• https://access.redhat.com/errata/RHSA-2026:60250

• https://access.redhat.com/errata/RHSA-2026:60249

• https://access.redhat.com/errata/RHSA-2026:60248

• https://access.redhat.com/errata/RHSA-2026:60247

• https://access.redhat.com/errata/RHSA-2026:60246

• https://access.redhat.com/errata/RHSA-2026:60239