CVE-2025-55164 json
content-security-policy-parser Prototype Pollution Vulnerability May Lead to RCE
published 2025-08-12 14 mo ago modified 2026-06-17 4 mo ago also GHSA-w2cq-g8g3-gm83 , EUVD-2025-24266
- cvss
- 8.8
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 40%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- npm content-security-policy-parser 0.6.0
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 14 mo ago
Exploit prediction
0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.8 | 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 |
| CNA | 4.0 | 8.8 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | content-security-policy-parser | <0.6.0 |
0.6.0 |
Affected products
- helmetjs content-security-policy-parser
Classification
- Weakness
-
- CWE-1321 Improperly Controlled Modification of Object Prototype Attributes
References
-
github.com
/helmetjs/content-security-policy-parser/commit/b13a52554f0168af393e3e38ed4a94e9e6aea9dc
web
-
github.com
/helmetjs/content-security-policy-parser/security/advisories/GHSA-w2cq-g8g3-gm83
web
-
github.com
/helmetjs/content-security-policy-parser/issues/11
web
- vicarius.io /vsociety/posts/cve-2025-55164-detect-node-csp-parser-vulnerability
- vicarius.io /vsociety/posts/cve-2025-55164-mitigate-csp-parser-vulnerability
-
nvd.nist.gov
/vuln/detail/CVE-2025-55164
advisory
-
github.com
/helmetjs/content-security-policy-parser
package
Sources
- CVE List CVE-2025-55164
- GitHub Advisory GHSA-w2cq-g8g3-gm83
- NVD CVE-2025-55164
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