Vulnerability · Published Oct 6, 2026 · Assigned by GitHub_M

CVE-2026-106488Backstage: Improper authentication in the OIDC provider

High 8.1

In plain English

A high-severity improper authentication in backstage from backstage. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.1High

Exploit odds (30 days)0.3%top 79.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Backstage is an open framework for building developer portals. Prior to 0.4.20, the @backstage/plugin-auth-backend-module-oidc-provider package is affected by improper authentication in the oidc provider. Deployments using OIDC email-based identity resolution with a provider that permits unverified email addresses may allow an authenticated provider user to assume another catalog identity. This may grant access and permissions associated with that user. No direct availability impact is demonstrated. This issue is fixed in version 0.4.20.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	@backstage/plugin-auth-backend-module-oidc-provider	0.4.20	GHSA-826h-28h9-65hg

Affected products (as reported)

Vendor	Product	Versions
backstage	backstage	< 1.54.6
@backstage	plugin-auth-backend-module-oidc-provider	< 0.4.20

Weakness: CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

References

https://github.com/backstage/backstage/security/advisories/GHSA-826h-28h9-65hg x_refsource_CONFIRM
https://github.com/backstage/backstage/commit/1b1f05e82161aaabc226c1d7d498d746956bf942 x_refsource_MISC
https://github.com/backstage/backstage/releases/tag/v1.54.6 x_refsource_MISC