Backstage is an open framework for building developer portals. Prior to 3.9.2 and from 4.0.0 until 4.0.2, DefaultCatalogRulesEnforcer in @backstage/plugin-catalog-backend compares the raw location.target URL against catalog.rules, while URL readers canonicalize the same URL before fetching it. An authenticated user with catalog.location.create permission can use percent-encoded path segments to make an untrusted URL match a trusted location pattern even though the canonical URL resolves outside that scope. This admits entity content from an untrusted source as trusted, while further downstream consequences depend on deployment configuration. This issue is fixed in versions 3.9.2 and 4.0.2.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 4
- StatusAwaiting Analysis → PublishedNVD modified 2026-10-26 17:56
- StatusPublished → Awaiting AnalysisNVD modified 2026-10-26 18:39
- StatusReceived → PublishedNVD modified 2026-10-26 17:56
- First seenCVSS 6.5NVD modified 2026-10-26 18:17
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 5
- https://github.com/backstage/backstage/commit/3214dc8f15d4a08a2fd07a72a8fe4d00aeac0db4
- https://github.com/backstage/backstage/commit/737ff1c719dbd5a97f375b7f1db6d61416618419
- https://github.com/backstage/backstage/releases/tag/v1.54.10
- https://github.com/backstage/backstage/releases/tag/v1.56.1
- https://github.com/backstage/backstage/security/advisories/GHSA-w658-mh9p-ww8f