CVE-2026-106498

HIGH 7.7

Backstage: Improper URL validation in catalog entity placeholder resolution

CVSS Score

7.7

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-863 CWE-918
Vendor	backstage
Product	backstage
Published	Oct 6, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

None

Availability

None

Affected Versions

backstage / backstage

< 1.49.6 >= 1.50.0-next.0, < 1.50.5 >= 1.51.0-next.0, < 1.51.3 >= 1.52.0-next.0, < 1.53.2 >= 1.54.0-next.0, < 1.54.6

@backstage / plugin-catalog-backend

< 3.5.1 >= 3.6.0, < 3.6.2 >= 3.7.0, < 3.7.2 >= 3.8.0, < 3.8.2 >= 3.9.0, < 3.9.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗