Backstage up to 3.9.0 plugin-catalog-backend input validation

Summaryinfo

A vulnerability described as problematic has been identified in Backstage up to 3.5.0/3.6.1/3.7.1/3.8.1/3.9.0. Affected is an unknown function of the component plugin-catalog-backend. Such manipulation leads to input validation. This vulnerability is documented as CVE-2026-106498. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Backstage up to 3.5.0/3.6.1/3.7.1/3.8.1/3.9.0. Affected by this issue is an unknown code block of the component plugin-catalog-backend. The manipulation with an unknown input leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Impacted is confidentiality. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-106498 since 10/06/2026. The exploitation is known to be easy. The attack may be launched remotely. There are neither technical details nor an exploit publicly available.

Upgrading to version 3.5.1, 3.6.2, 3.7.2, 3.8.2 or 3.9.1 eliminates this vulnerability.

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Productinfo

Name

• Backstage

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.5.0
• 3.6
• 3.6.0
• 3.6.1
• 3.7
• 3.7.0
• 3.7.1
• 3.8
• 3.8.0
• 3.8.1
• 3.9.0

Website

• Product: https://github.com/backstage/backstage/

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