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No exploitation reportedFix available

CVE-2021-23436

No exploitation reported by the sources we read.

  • Published2021-09-01
  • Fixed in9.0.6
  • WeaknessCWE-843

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-09-0118:15CVE publishedNVD

Versions per branch

NVD · OSV
Immer project immer
BranchAffectedFixed in
9.0< 9.0.69.0.6
9.0≥ 7.0.0, < 9.0.69.0.6

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • @rootio/immerRoot:npmall versions · fixed in 8.0.1-root.io.1
  • @rootio/immerRoot:npmall versions · fixed in 8.0.1-root.io.2
  • immerTuxCare:npmfrom 8.0.1-tuxcare.0 · fixed in 8.0.1-tuxcare.1
  • immerRoot:npmall versions · fixed in 8.0.1-aikido.1
  • immerRoot:npmall versions · fixed in 8.0.1-aikido.2

Vendor advisories

  • CVE-2021-23436 Red Hat Product Security1 product fixed · 1 known affected

    immer: type confusion vulnerability can lead to a bypass of CVE-2020-28477

    immer as a component of Red Hat Process Automation 7

  • RHSA-2022:6813 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Process Automation Manager 7.13.1 security update

Full record on NVD

Fix

  1. Update Immer project immer to 9.0.6
  2. Vendor fix Red Hat Product Security RHSA-2022:6813 · 1 productFor on-premise installations, before applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on. Red Hat recommends that you halt the server by stopping the JBoss Application Server process before installing …
  3. No fix planned, says the vendor Red Hat Product Security CVE-2021-23436 · 1 productOut of support scope

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CNACVSS 3.15.6known since 2026-10-23
  • NVDCVSS 3.19.8read 2026-10-23
  • NVDCVSS 2.07.5read 2026-10-23
  • NVDweakness (CWE)CWE-843read 2026-10-23
  • FIRST EPSSEPSS score1.8 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryCRITICAL2021-09-02

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2021-09-01
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-33f9-j839-rf8h

Frequently asked questions

What is CVE-2021-23436?

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.

Is CVE-2021-23436 actively exploited?

Active exploitation of CVE-2021-23436 has not been confirmed. Its EPSS score was 1.8% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-23436?

CVE-2021-23436 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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