CVE-2021-23436

highpriority · track · 40EPSS 0.018 · 78 %ileEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

1.80% (78th) EPSS

CVSS 7.5 · high

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

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

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 5.6–9.8

v2.07.5highAV:N/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 10 · impact 6.4

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 5.9

v3.15.6mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:Csecondary · ENISA EU

v3.15.6mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:Lsecondary · report@snyk.ioexploitability 2.2 · impact 3.4

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · OSV

v3.19criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-843USprimaryCWE-1321USCWE-843US

affected products (3)

Products and version ranges known to be affected.

n/a immerunspecified → 9.0.6enisa_euvdEU
immer project immer< 9.0.6nvdUScpe:2.3:a:immer_project:immer:*:*:*:*:*:*:*:*
npm immer7.0.0 → 9.0.6osvUSpkg:npm/immer

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-33f9-j839-rf8hPrototype Pollution in immer2021-09-02ghsa · osvUS
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.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2021-09-01modified 2026-06-17

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+1194 more

references (12)

External citations — patches, advisories, analysis.

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