# Jenkins Open Redirect via Relative Path Segments in Post-Login Redirect URL

Advisory record · `GHSA-3rqh-hch3-jhpc`

- **Identifiers:** `GHSA-3rqh-hch3-jhpc` · `BIT-jenkins-2026-53436` · `CVE-2026-53436`
- **State:** Confirmed
- **Severity:** CVSS 4.3 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-601](https://cwe.mitre.org/data/definitions/601.html)
- **Tags:** [Open redirect](https://agentprime.io/advisories/tag/open-redirect.md)
- **Published:** 10 Jun 2026
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 10 Jun 2026, 15:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `org.jenkins-ci.main:jenkins-core` (Maven): affected `>=2.556, <2.568 || <2.555.3`; fixed in `2.568`, `2.555.3`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Jenkins core (org.jenkins-ci.main:jenkins-core) versions from 2.556 before 2.568, and versions before 2.555.3, are affected. Jenkins improperly treats a post-login redirect URL containing relative path segments as pointing to Jenkins, so an attacker can craft a link that sends users to an external site after login, enabling phishing. Upgrade to 2.568 or 2.555.3, or to a later fixed release.

Written 2 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 4.3 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.0026, the 17th percentile, on 9 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:17 UTC: First seen by agentprime
- 31 Oct 2026, 14:17 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-3rqh-hch3-jhpc)

## Sources

- [GitHub Advisory Database: GHSA-3rqh-hch3-jhpc](https://github.com/advisories/GHSA-3rqh-hch3-jhpc)
- [OSV: GHSA-3rqh-hch3-jhpc](https://osv.dev/vulnerability/GHSA-3rqh-hch3-jhpc)
- <https://nvd.nist.gov/vuln/detail/CVE-2026-53436>
- <https://github.com/jenkinsci/jenkins/commit/8ef52891b07eb639b38271e4bab5dab3c0f10fda>
- <https://github.com/jenkinsci/jenkins/commit/b32f2f27a82ed187a34f55b05edcc4a83563d574>
- <https://github.com/jenkinsci/jenkins>
- <https://www.jenkins.io/security/advisory/2026-06-10/#SECURITY-3711+3755>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-3rqh-hch3-jhpc>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-3rqh-hch3-jhpc/>. Everything for agents: <https://agentprime.io/llms.txt>.