Cross-Site Scripting vulnerability in @backstage/plugin-auth-backend
Impact
This vulnerability 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.
Patches
This is vulnerability is patched in version 0.4.9 of @backstage/plugin-auth-backend.
For more information
If you have any questions or comments about this advisory:
- Open an issue in the Backstage repository
- Visit our chat, linked to in Backstage README
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @backstage/plugin-auth-backend | < 0.4.9 | 0.4.9 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N- Weakness (CWE)
CWE-79- Platform
- npm
- Package
@backstage/plugin-auth-backend- Disclosed
- 01.12.2021
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-w7fj-336r-vw49 - CC BY 4.0
Vulnerability history: @backstage/plugin-auth-backend
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 4
- First → latest
- 12.2021 07.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 2
- Low 1
Disclosures per year
- 2021: 1
- 2022: 0
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 3
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Cross-Site Scripting vulnerability in @backstage/plugin-auth-backend this entry
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