PatchTheCVECVE-2026-53440: Jenkins 2.567 and earlier, LTS 2.555.2 and earlier does not ensure that the "from" parameter in the "Delegate
CVE-2026-53440 is a medium-severity flaw (CVSS 4.3) affecting jenkins. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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.
Why this priority
- No elevated risk signals yet
A fixed release or distro patch exists.
Risk facts
| CVSS score | 4.3 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | Required |
| EPSS exploit chance | 0.2% (top 86%) |
| CISA exploited list | No |
| Weakness | CWE-601 |
| Published | 2026-06-10 |
| Last modified | 2026-10-26 |
Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-53440?
jenkins: upgrade to 2.555.3, 2.568. Exact commands for each OS are on this page.
Is CVE-2026-53440 being exploited?
CVE-2026-53440 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-53440 affect?
CVE-2026-53440 affects jenkins. Severity is medium (CVSS 4.3). 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 redirec
How urgent is CVE-2026-53440?
Priority 18/100. No elevated risk signals yet.
Software pages
Related CVEs
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