CVE-2026-115923
mediumBackstage is an open framework for building developer portals.
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/backstage/backstage/commit/3214dc8f15d4a08a2fd07a72a8fe4d00aeac0db4 security-advisories@github.com
- https://github.com/backstage/backstage/commit/737ff1c719dbd5a97f375b7f1db6d61416618419 security-advisories@github.com
- https://github.com/backstage/backstage/releases/tag/v1.54.10 security-advisories@github.com
- https://github.com/backstage/backstage/releases/tag/v1.56.1 security-advisories@github.com
- https://github.com/backstage/backstage/security/advisories/GHSA-w658-mh9p-ww8f security-advisories@github.com