Most recent entries from all

EUVD-2026-275912

fkie_cve-2026-32235

Backstage is an open framework for building developer portals. Prior to 0.27.1, the experimental OIDC provider in @backstage/plugin-auth-backend is vulnerable to a redirect URI allowlist bypass. Instances that have enabled experimental Dynamic Client Registration or Client ID Metadata Documents and configured allowedRedirectUriPatterns are affected. A specially crafted redirect URI can pass the allowlist validation while resolving to an attacker-controlled host. If a victim approves the resulting OAuth consent request, their authorization code is sent to the attacker, who can exchange it for a valid access token. This requires victim interaction and that one of the experimental features is explicitly enabled, which is not the default. This vulnerability is fixed in 0.27.1.

GHSA-wqvh-63mv-9w92 — @backstage/plugin-auth-backend: OAuth redirect URI allowlist bypass

Affected: npm: @backstage/plugin-auth-backend

### Impact

The experimental OIDC provider in `@backstage/plugin-auth-backend` is vulnerable to a redirect URI allowlist bypass. Instances that have enabled experimental Dynamic Client Registration or Client ID Metadata Documents and configured `allowedRedirectUriPatterns` are affected.

A specially crafted redirect URI can pass the allowlist validation while resolving to an attacker-controlled host. If a victim approves the resulting OAuth consent request, their authorization code is sent to the attacker, who can exchange it for a valid access token.

This requires victim interaction and that one of the experimental features is explicitly enabled, which is not the default.

### Patches

Upgrade to `@backstage/plugin-auth-backend` version 0.27.1 or later.

### Workarounds

Disable experimental Dynamic Client Registration and Client ID Metadata Documents features if they are not required.

### References

- [RFC 6749 Section 3.1.2 - Redirection Endpoint](https://datatracker.ietf.org/doc/html/rfc6749#section-3.1.2)

RHSA-2026:24841 — Red Hat Security Advisory: Red Hat Developer Hub 1.10.0 release.

lodash: Lodash: Prototype pollution allows deletion of built-in prototype properties via array path bypass path-to-regexp: path-to-regexp: Denial of Service via specially crafted paths with multiple wildcards undici: Undici: Denial of Service via excessive decompression steps Underscore.js: Underscore.js: Denial of Service via recursive data structures in flatten and isEqual functions yauzl: yauzl: Denial of Service vulnerability in zip file processing @backstage/plugin-auth-backend: @backstage/plugin-auth-backend: OAuth redirect URI allowlist bypass fast-xml-parser: fast-xml-parser: Denial of Service via unbounded entity expansion due to incorrect configuration limit handling