{"cve":"CVE-2021-23436","nvd":{"published":"2021-09-01T18:15:08.477","modified":"2026-06-17T03:38:45.597","status":"Modified","description":"This affects the package immer before 9.0.6. A type confusion vulnerability can lead to a bypass of CVE-2020-28477 when the user-provided keys used in the path parameter are arrays. In particular, this bypass is possible because the condition (p === \"__proto__\" || p === \"constructor\") in applyPatches_ returns false if p is ['__proto__'] (or ['constructor']). The === operator (strict equality operator) returns false if the operands have different type.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-843"],"references":["https://github.com/immerjs/immer/commit/fa671e55ee9bd42ae08cc239102b665a23958237","https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1579266","https://snyk.io/vuln/SNYK-JS-IMMER-1540542","https://github.com/immerjs/immer/commit/fa671e55ee9bd42ae08cc239102b665a23958237","https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1579266"],"products":["immer_project:immer"],"source":"nvd","synced_at":"2026-10-19T21:21:57.125947417+00:00"},"epss":{"cve":"CVE-2021-23436","score":0.01795,"percentile":0.78424,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-33f9-j839-rf8h","url":"https://osv.dev/vulnerability/GHSA-33f9-j839-rf8h","summary":"Prototype Pollution in immer","modified":"2025-01-14T09:12:14.521021Z","packages":[{"ecosystem":"npm","name":"immer","purl":"pkg:npm/immer","ranges":[">=7.0.0 <9.0.6"],"fixed":["9.0.6"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}