CVE-2026-106495 Backstage: Improper access control in backend action invocation
Authenticated users can bypass operator-configured action exclusions in Backstage backend-defaults, invoking restricted actions despite existing downstream authorization checks.
- 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-2026-106495?
CVE-2026-106495 is a medium-severity missing authorization vulnerability in @backstage backend-defaults, published on 12 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 0.17.8, the @backstage/backend-defaults package is affected by improper access control in backend action invocation. An authenticated user could invoke actions that an operator had excluded through action configuration. Existing action permissions and downstream authorization remain enforced. This issue is fixed in version 0.17.8.
Weakness: CWE-284
Which versions are affected by CVE-2026-106495?
2 open source packages ship an affected version, including @backstage/backend-defaults.
| Package | Affected | Fixed in |
|---|---|---|
@backstage/backend-defaults npm | All versions | 0.17.8 |
@backstage/backend-defaults npm | All versions | 0.17.8 |
How do I fix CVE-2026-106495?
Upgrade @backstage/backend-defaults to 0.17.8 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-106495 being exploited?
There is no known exploitation of CVE-2026-106495 in the wild and no public exploit code.
Sources
Also known as GHSA-3xr5-8w6c-p5gw.