A AegiFlow
MEDIUMCVSS 6.5EPSS 0.3%

CVE-2026-115923

CVE-2026-115923 updated by NVD

Published
2026-10-28
Modified
2026-11-04
EPSS percentile
25%
Sources
github-advisory, nvd

Summary

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.

Affected packages

EcosystemPackageAffected versionsFixed versions
npm@backstage/plugin-catalog-backend—3.9.2, 4.0.2

Remediation: Upgrade to 3.9.2 or later.

References

Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.

Includes data from the National Vulnerability Database (NIST). NVD data is in the public domain; this page is not endorsed by NIST.

CVE® is a registered trademark of The MITRE Corporation. CVE content reproduced under the CVE Terms of Use; copyright designation © MITRE.

EPSS scores provided by the FIRST.org Exploit Prediction Scoring System.