CVE-2021-23518
CVSS v3
9.8
CRITICAL
EPSS Score
1.9 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
The package cached-path-relative before 1.1.0 are vulnerable to Prototype Pollution via the cache variable that is set as {} instead of Object.create(null) in the cachedPathRelative function, which allows access to the parent prototype properties when the object is used to create the cached relative path. When using the origin path as __proto__, the attribute of the object is accessed instead of a path. **Note:** This vulnerability derives from an incomplete fix in https://security.snyk.io/vuln/SNYK-JS-CACHEDPATHRELATIVE-72573
Technical details
- Published
- 2022-01-21
Frequently asked questions
What is CVE-2021-23518?
The package cached-path-relative before 1.1.0 are vulnerable to Prototype Pollution via the cache variable that is set as {} instead of Object.create(null) in the cachedPathRelative function, which allows access to the parent prototype properties when the object is used to create the cached relative path. When using the origin path as __proto__, the attribute of the object is accessed instead of a path. **Note:** This vulnerability derives from an incomplete fix in https://security.snyk.io/vuln/SNYK-JS-CACHEDPATHRELATIVE-72573
Is CVE-2021-23518 actively exploited?
Active exploitation of CVE-2021-23518 has not been confirmed. Its EPSS score was 1.9% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-23518?
CVE-2021-23518 has a CVSS v3 base score of 9.8 (CRITICAL severity).
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