CVSS 3.1
6.1 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NCVE-2021-43776
Medium (6.1) in linuxfoundation auth backend. EPSS 0.7% chance of exploitation in the next 30 days. Fixed in @backstage/plugin-auth-backend 0.4.9.
Backstage is an open platform for building developer portals. In affected versions the auth-backend plugin allows a malicious actor to trick another user into visiting a vulnerable URL that executes an XSS attack. This attack can potentially allow the attacker to exfiltrate access tokens or other secrets from the user's browser. The default CSP does prevent this attack, but it is expected that some deployments have these policies disabled due to incompatibilities. This is vulnerability is patched in version `0.4.9` of `@backstage/plugin-auth-backend`.
Severity
- EPSS
- 0.7% chance of exploitation in the next 30 days; higher than 52% of CVEs (scores of 2026-10-31)
- CWE
- CWE-79
- Published
- Modified
- Record from
- the NVD, synced
Affected
- linuxfoundation:auth_backend
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-w7fj-336r-vw49 | npm | @backstage/plugin-auth-backend | <0.4.9 | 0.4.9 |