Configuration Override in helmet-csp
Versions of helmet-csp before to 2.9.1 are vulnerable to a Configuration Override affecting the application's Content Security Policy (CSP). The package's browser sniffing for Firefox deletes the default-src CSP policy, which is the fallback policy. This allows an attacker to remove an application's default CSP, possibly rendering the application vulnerable to Cross-Site Scripting.
Recommendation
Upgrade to version 2.9.1 or later. Setting the browserSniff configuration to false in vulnerable versions also mitigates the issue.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | helmet-csp | >= 1.2.2, < 2.9.1 | 2.9.1 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N- Weakness (CWE)
-- Platform
- npm
- Package
helmet-csp- Disclosed
- 03.09.2020
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-c3m8-x3cg-qm2c - CC BY 4.0
Vulnerability history: helmet-csp
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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