content-security-policy-parser Prototype Pollution Vulnerability May Lead to RCE
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.8epss 0.4%
exploitation probability
0.4%top 64% of all CVEs
observed exploitation
nono source reports it
content-security-policy-parser parses content security policy directives. A prototype pollution vulnerability exists in versions 0.5.0 and earlier, wherein if a policy name is called __proto__, one can override the Object prototype. This issue has been patched in version 0.6.0. A workaround involves disabling prototype method in NodeJS, neutralizing all possible prototype pollution attacks. Provide either --disable-proto=delete (recommended) or --disable-proto=throw as an argument to node to enable this feature.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
Affected products
helmetjs · content-security-policy-parserReferences
https://github.com/helmetjs/content-security-policy-parser/commit/b13a52554f0168af393e3e38ed4a94e9e6aea9dchttps://github.com/helmetjs/content-security-policy-parser/issues/11https://github.com/helmetjs/content-security-policy-parser/security/advisories/GHSA-w2cq-g8g3-gm83https://www.vicarius.io/vsociety/posts/cve-2025-55164-detect-node-csp-parser-vulnerabilityhttps://www.vicarius.io/vsociety/posts/cve-2025-55164-mitigate-csp-parser-vulnerability