CVE-2026-115923
Backstage is an open framework for building developer portals
- Risk score
- 44/100
- CVSS
- 6.5 v3.1
- Exploit chance (30 days)
- 0.3%
- Published
- 26 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- 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 wi…
- Affected
- See advisory
- Fix
- Upgrade the product to 3.9.2 or 4.0.2 (whichever matches your release line), or later.
- Exploitation
- No known exploitation
Why it is Yellow
- CVSS 6.5 medium
References
- 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
Original description
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.
Last activity 26 Oct 2026. Patch Forecast updates every hour.