CVE-2026-32235

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

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.

The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.

CVE-2026-32235 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.27.1); upgrading removes the vulnerable code path.

Kodem intelligence

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

1. What is CVE-2026-32235? CVE-2026-32235 is a medium-severity improper input validation vulnerability in @backstage/plugin-auth-backend (npm), affecting versions < 0.27.1. It is fixed in 0.27.1. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
2. How severe is CVE-2026-32235? CVE-2026-32235 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of @backstage/plugin-auth-backend are affected by CVE-2026-32235? @backstage/plugin-auth-backend (npm) versions < 0.27.1 is affected.
4. Is there a fix for CVE-2026-32235? Yes. CVE-2026-32235 is fixed in 0.27.1. Upgrade to this version or later.
5. Is CVE-2026-32235 exploitable, and should I be worried? Whether CVE-2026-32235 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-32235 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-32235? Upgrade @backstage/plugin-auth-backend to 0.27.1 or later.