---
id: "CVE-2026-112212"
kind: "vulnerability"
aliases: ["CVE-2026-112212"]
title: "GitLab: poisoned OAuth discovery cache can redirect login flows externally"
severity: "high"
cvss: 7.5
epss: 0.0019
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["gitlab", "oauth", "oidc", "runtime", "self-hosted"]
not_affected_if: ["gitlab-com", "unaffected-version"]
published_at: "2026-10-22T01:16:57+00:00"
first_seen_at: "2026-10-23T21:57:29+00:00"
updated_at: "2026-10-25T03:16:19+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-112212", "first_seen_at": "2026-10-23T21:57:29+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-112212", "first_seen_at": "2026-10-24T07:15:52+00:00"}]
---

# GitLab: poisoned OAuth discovery cache can redirect login flows externally

GitLab CE and EE cache OAuth/OIDC discovery documents, and an unauthenticated user could poison that shared cache so certain authentication flows are sent to a server they control. That can expose login credentials or tokens to the attacker under certain conditions.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed GitLab version with `gitlab-rake gitlab:env:info` or the Admin Area, and compare it to the affected ranges: 18.3 before `19.3.6`, 19.4 before `19.4.3`, and 19.5 before `19.5.1`.
- Check whether OAuth or OIDC sign-in is enabled in the GitLab configuration.

## Fix

- Upgrade GitLab CE/EE to `19.3.6`, `19.4.3`, `19.5.1` or later, matching your release line.

## Timeline

- 2026-10-23T21:57:29+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-112212
- 2026-10-24T07:15:52+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-112212

## From the sources

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.3 before 19.3.6, 19.4 before 19.4.3, and 19.5 before 19.5.1 that, under certain conditions, an unauthenticated user could have poisoned a shared cache's OAuth/OIDC discovery document to redirect certain flows to an externally controlled server, due to improper trust of user-supplied values when constructing endpoint URLs in cached discovery responses.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_