CVE-2026-106498

Received Received - Intake

Improper URL Validation in Backstage Catalog Backend

Publication date: 2026-10-06

Last updated on: 2026-10-06

Assigner: GitHub, Inc.

Description

Backstage is an open framework for building developer portals. Prior to 3.5.1, 3.6.2, 3.7.2, 3.8.2 and 3.9.1, the @backstage/plugin-catalog-backend package is affected by improper url validation in catalog entity placeholder resolution. An authenticated Backstage user could craft a catalog entity with placeholder directives that reference resources outside the entity's source repository. Under certain configurations, this could allow access to data not intended to be available to the user. This issue is fixed in versions 3.5.1, 3.6.2, 3.7.2, 3.8.2 and 3.9.1.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-10-06

Last Modified

2026-10-06

Generated

2026-10-07

AI Q&A

2026-10-07

EPSS Evaluated

N/A

NVD

CVE-2026-106498

Affected Vendors & Products

Vendor	Product	Version / Range
backstage	backstage	< 1.49.6
backstage	backstage	>= 1.50.0-next.0, < 1.50.5
backstage	backstage	>= 1.51.0-next.0, < 1.51.3
backstage	backstage	>= 1.52.0-next.0, < 1.53.2
backstage	backstage	>= 1.54.0-next.0, < 1.54.6
@backstage	plugin-catalog-backend	< 3.5.1
@backstage	plugin-catalog-backend	>= 3.6.0, < 3.6.2
@backstage	plugin-catalog-backend	>= 3.7.0, < 3.7.2
@backstage	plugin-catalog-backend	>= 3.8.0, < 3.8.2
@backstage	plugin-catalog-backend	>= 3.9.0, < 3.9.1

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-918	The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
CWE-863	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.

Attack-Flow Graph

Executive Summary

This vulnerability in Backstage's @backstage/plugin-catalog-backend package allows improper URL validation during catalog entity placeholder resolution. An authenticated user could create a catalog entity with placeholder directives that access resources outside the entity's source repository. This could lead to unauthorized data exposure under certain configurations.

Impact Analysis

An attacker with access to Backstage could exploit this to read sensitive data not intended for them. This includes configuration files, secrets, or other restricted resources. The impact depends on the Backstage deployment and data stored within it.

Compliance Impact

This vulnerability could lead to unauthorized data access, violating GDPR's data protection principles or HIPAA's confidentiality requirements. Organizations using Backstage may face compliance violations if sensitive data is exposed.

Mitigation Strategies

Update the @backstage/plugin-catalog-backend package to version 3.5.1, 3.6.2, 3.7.2, 3.8.2 or 3.9.1 or later to address the improper URL validation issue.

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