CVE-2026-106458: Backstage Inconsistent Repository Filtering Vulnerability
MODERATECVE-2026-106458 is a MODERATE (CVSS 6.5) inconsistent repository filtering vulnerability (CWE-863: Incorrect Authorization) affecting Backstage libraries in the npm ecosystem. The issue involves inconsistent repository filtering in bitbucket server catalog event updates. Remediation is available by upgrading affected packages to version 0.5.15.
CVE-2026-106458 at a Glance
Security Impact
CVSS: 6.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N).
How to Fix CVE-2026-106458
To remediate this vulnerability, upgrade all affected Backstage dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
npm install @backstage/plugin-catalog-backend-module-bitbucket-server@0.5.15Run the following command in your project directory to verify that all resolved dependencies use the patched release:
npm ls @backstage/plugin-catalog-backend-module-bitbucket-serverHow to Check if You Are Affected
To determine whether your Node.js application is affected by CVE-2026-106458, inspect your project dependencies using npm:
npm ls @backstage/plugin-catalog-backend-module-bitbucket-serverAnalyze the terminal output to locate any version of Backstage in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.5.15), your application is affected.
Note: The npm ls @backstage/plugin-catalog-backend-module-bitbucket-server command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-863: Incorrect Authorization, where the product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. In Backstage, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-106458 Affected Backstage Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
@backstage/plugin-catalog-backend-module-bitbucket-server
|
npm |
≥ 0.4.0
< 0.5.15
|
0.5.15
|
References
Frequently Asked Questions
What is CVE-2026-106458?
Which Backstage versions are affected?
What version fixes CVE-2026-106458?
Is @backstage/plugin-catalog-backend-module-bitbucket-server affected?
What is the CVSS score of CVE-2026-106458?
What CWE is associated with CVE-2026-106458?
How can I check npm dependencies for CVE-2026-106458?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-c36c-cf6r-ghgj",
"modified" : "2026-10-07T20:25:08Z",
"published" : "2026-10-07T20:25:08Z",
"aliases" : [ "CVE-2026-106458" ],
"summary" : " Backstage: Inconsistent repository filtering in Bitbucket Server catalog event updates",
"details" : "### Impact\n\nDeployments 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.\n\nAn 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 can cause catalog entities and metadata to be ingested from a repository that the operator did not intend to trust.\n\nDeployments that do not enable event support for the Bitbucket Server catalog provider, do not configure repository filters, or whose integration credentials cannot read the filtered-out repositories are not affected.\n\n### Patches\n\nUpgrade `@backstage/plugin-catalog-backend-module-bitbucket-server` to version `0.5.15` or later. The fixed package is available in [Backstage v1.55.0](https://github.com/backstage/backstage/releases/tag/v1.55.0).\n\n### Workarounds\n\n- Disable event-driven updates for the Bitbucket Server catalog provider and rely on scheduled discovery until the patched package is deployed.\n- Restrict the configured Bitbucket Server integration credentials so that they cannot read repositories that must remain outside the catalog trust boundary.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "npm",
"name" : "@backstage/plugin-catalog-backend-module-bitbucket-server"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0.4.0"
}, {
"fixed" : "0.5.15"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/backstage/backstage/security/advisories/GHSA-c36c-cf6r-ghgj"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-106458"
}, {
"type" : "WEB",
"url" : "https://github.com/backstage/backstage/commit/989db63b6f87c8fc04d440f296ad89e10c79b363"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/backstage/backstage"
}, {
"type" : "WEB",
"url" : "https://github.com/backstage/backstage/releases/tag/v1.55.0"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-863" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-10-07T20:25:08Z",
"nvd_published_at" : "2026-10-06T21:17:16Z"
}
}