CVE-2026-106458: Backstage: Inconsistent repository filtering in Bitbucket Server catalog event updates

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-06 · updated 2026-10-27
Weakness: CWE-863

Description

Backstage is an open framework for building developer portals. From 0.4.0 until 0.5.15, the @backstage/plugin-catalog-backend-module-bitbucket-server package is affected by inconsistent repository filtering in bitbucket server catalog event updates. Deployments using event-driven updates in the Bitbucket Server catalog provider may ingest catalog locations from repositories that are excluded by the provider's configured project, repository, or archived-repository filters. An authenticated Bitbucket Server user who can push to a filtered-out repository that remains readable by the configured Backstage integration can trigger a legitimate repository event. The affected event path may then add a Location for that repository even though scheduled discovery excludes it. This issue is fixed in version 0.5.15.

Affected products

backstage: from 1.38.0 before 1.55.0 — fixed in 1.55.0
Linuxfoundation Backstage/Plugin-Catalog-Backend-Module-Bitbucket-Server: from 0.4.0 before 0.5.15 — fixed in 0.5.15
backstage: from 1.38.0, < 1.55.0
@backstage plugin-catalog-backend-module-bitbucket-server: from 0.4.0, < 0.5.15

How to fix

Upgrade to a fixed version: backstage 1.55.0; Linuxfoundation Backstage/Plugin-Catalog-Backend-Module-Bitbucket-Server 0.5.15. Check the vendor advisory for mitigations.

References

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