What is CVE-2026-53440?

CVE-2026-53440 is a medium-severity vulnerability in Jenkins, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 4.3/10. Published 2026-06-10.

How severe is CVE-2026-53440?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Open Redirect in Jenkins

CVE-2026-53440

Jenkins 2.567 and earlier, LTS 2.555.2 and earlier does not ensure that the "from" parameter in the "Delegate to servlet container" security realm is safe to redirect to after login, allowing attackers to perform phishing attacks by redirecting users to an attacker-controlled domain.

Vulnerability class: Open Redirect

Published 2026-06-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (27.7th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 27.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.001

Affected products

Jenkins
Jenkins Project — versions 2.568, 2.555.3

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

www.jenkins.io/security/advisory/2026-06-10/ (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-53440?: CVE-2026-53440 is a medium-severity vulnerability in Jenkins, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 4.3/10. Published 2026-06-10.
How severe is CVE-2026-53440?: Medium severity. CVSS v3 base score is 4.3 out of 10.