{"answers":{"affected":"2 open source packages ship an affected version, including @backstage/plugin-auth-backend. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-73563 in the wild and no public exploit code.","fix":"Upgrade @backstage/plugin-auth-backend to 0.29.2 or later.","what":"CVE-2026-73563 is a medium-severity vulnerability in backstage, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-73563 and fix it if it is affected.\n\nWhat it is: CVE-2026-73563 is a medium-severity vulnerability in backstage, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2026-73563 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- @backstage/plugin-auth-backend (npm): affected all versions; fixed in 0.29.2\n- @backstage/plugin-auth-backend (npm): affected all versions; fixed in 0.29.2\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-73563/ (Markdown: https://insights.sbomify.com/CVE-2026-73563/index.md)","id":"CVE-2026-73563","markdown":"https://insights.sbomify.com/CVE-2026-73563/index.md","name":"CVE-2026-73563","record":{"aliases":["GHSA-38hq-7x33-php4"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["account_takeover"],"network_reachable":"yes","non_default_config":true,"product_category":"Backstage developer portal","requires_auth":"none","summary":"Attackers can bypass OAuth redirect URI allowlists in experimental Backstage auth features to steal authorization codes and take over accounts.","user_interaction":"required","vuln_class":"open_redirect"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"backstage\\/plugin-auth-backend","vendor":"linuxfoundation"}],"cvss":{"score":4.7,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","version":"3.1"},"cwes":[{"id":"CWE-601","name":"URL Redirection to Untrusted Site"}],"description":"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.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"@backstage/plugin-auth-backend: Unauthenticated OAuth account takeover via `redirect_uri` allowlist bypass","id":"CVE-2026-73563","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"open_redirect","year":"2026"},"n_packages":2,"n_references":1,"next":{"headline":"frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow","id":"CVE-2026-73564"},"packages":[{"ecosystem":"npm","fixed":["0.29.2"],"introduced":["0"],"last_affected":[],"package":"@backstage/plugin-auth-backend","purl":null,"source":"GHSA-38hq-7x33-php4"},{"ecosystem":"npm","fixed":["0.29.2"],"introduced":["0"],"last_affected":[],"package":"@backstage/plugin-auth-backend","purl":"pkg:npm/%40backstage/plugin-auth-backend","source":"GHSA-38hq-7x33-php4"}],"prev":{"headline":"Mongoose: Prototype pollution in the update casting via __proto__-prefixed dotted path (Schema._getSchema/path getter)","id":"CVE-2026-73562"},"products":["backstage"],"published":"2026-08-13","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-13","vendors":["backstage"]},"summary":"Attackers can bypass OAuth redirect URI allowlists in experimental Backstage auth features to steal authorization codes and take over accounts.","url":"https://insights.sbomify.com/CVE-2026-73563/"}