Vulnerability · CVE-2026-73563
Linux Foundationのbackstage/plugin-auth-backendにおけるオープンリダイレクトの脆弱性
Published Aug 13, 2026 · corrected/updated Aug 13, 2026 · backstage backstage · evidence confidence high
Backstage is an open framework for building developer portals. Prior to 0.29.2, the experimental dynamic client registration and client ID metadata document features in the @backstage/plugin-auth-backend use full-string matcher.isMatch glob matching for auth.experimentalDynamicClientRegistration.allowedRedirectUriPatterns and the auth.experimentalClientIdMetadataDocuments allowedClientIdPatterns and allowedRedirectUriPatterns options. A hostname wildcard can match across URL component boundaries, allowing an attacker-controlled redirect URI with a trusted hostname suffix in its path to pass the allowlist and receive an OAuth authorization code after a victim completes the flow. Patterns without an explicit protocol can match unintended protocols, and redirect URIs containing embedded credentials are accepted after user information is stripped for matching. The features are experimental and disabled by default; only deployments that enable them and configure custom wildcard-hostname or protocol-less patterns are affected. This issue is first fixed in prerelease version 0.29.2.
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-73563 is a medium public vulnerability record for backstage backstage. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether backstage backstage is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: backstage backstage. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 4.7, EPSS 0.2%. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-601. Sources contributing to this record: cve_org, epss, jvndb. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Aug 13, 2026 · CVE.org
Updated
Backstage is an open framework for building developer portals. Prior to 0.29.2, the experimental dynamic client registration and client ID metadata document features in the @backstage/plugin-auth-backend use full-string matcher.isMatch glob matching for auth.experimentalDynamicClientRegistration.allowedRedirectUriPatterns and the auth.experimentalClientIdMetadataDocuments allowedClientIdPatterns a
Oct 16, 2026 · JVN iPedia
Detected
Backstageは開発者ポータルを構築するためのオープンフレームワークです。バージョン0.29.2以前では、@backstage/plugin-auth-backendの実験的な動的クライアント登録機能およびクライアントIDメタデータドキュメント機能において、auth.experimentalDynamicClientRegistration.allowedRedirectUriPatternsおよびauth.experimentalClientIdMetadataDocumentsのallowedClientIdPatternsとallowedRedirectUriPatternsオプションで、full-string matcher.isMatchのグロブマッチングが使われていました。ホスト名のワイルドカードはURLコンポーネントの境界を超えてマッチできるため、攻撃者が制御するリダイレ
Affected
- vendor backstage backstageversion unspecified
Sources
- CVE.orgVulnerability recordCVE-2026-73563
Backstage is an open framework for building developer portals. Prior to 0.29.2, the experimental dynamic client registration and client ID metadata document features in the @backstage/plugin-auth-backend use full-string matcher.isMatch glob matching for auth.experimentalDynamicCl
cve.org - FIRST EPSSExploitation probabilityCVE-2026-73563
30-day exploitation probability 0.2%
first.org - JVN iPediaGovernment advisoryCVE-2026-73563
Backstageは開発者ポータルを構築するためのオープンフレームワークです。バージョン0.29.2以前では、@backstage/plugin-auth-backendの実験的な動的クライアント登録機能およびクライアントIDメタデータドキュメント機能において、auth.experimentalDynamicClientRegistration.allowedRedirectUriPatternsおよびauth.experimentalClientIdMetadataDocumentsのallowedClientIdPatternsとallowedRed
jvndb.jvn.jp