CVE-2026-106498 Backstage: Improper URL validation in catalog entity placeholder resolution
Authenticated users can exploit improper URL validation in catalog placeholders to access unauthorized internal resources under specific configurations.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-106498?
CVE-2026-106498 is a high-severity server-side request forgery vulnerability in Linuxfoundation Backstage, published on 6 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-106498?
2 open source packages ship an affected version, including @backstage/plugin-catalog-backend. It affects 2 products.
| Package | Affected | Fixed in |
|---|---|---|
@backstage/plugin-catalog-backend npm | All versions | 3.9.1 |
@backstage/plugin-catalog-backend npm | All versions | 3.9.1 |
Products include Linuxfoundation Backstage, Linuxfoundation Backstage Plugin-Catalog-Backend.
How do I fix CVE-2026-106498?
Upgrade @backstage/plugin-catalog-backend to 3.9.1 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-106498 being exploited?
There is no known exploitation of CVE-2026-106498 in the wild and no public exploit code.
Other vulnerabilities in Linuxfoundation Backstage
- CVE-2026-106501 Backstage: Sensitive information exposure in Scaffolder
- CVE-2026-106558 Backstage: Improper validation of TechDocs MkDocs configuration
- CVE-2026-88064 Backstage: Improper input validation in TechDocs MkDocs configuration
- CVE-2026-106459 Backstage: Improper input validation in Sentry scaffolder actions
- CVE-2026-106486 Backstage: Improper filesystem validation in Bitbucket pull-request scaffolder actions
Sources
Also known as GHSA-qgvj-qcf8-xq73.