CVE-2021-23558

Name: CVE-2021-23558
Creator: NVD / NIST
Published: 2022-01-28T22:15:09.073+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.63%

Last modified Jun 17, 2026

CVE-2021-23558 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. The package bmoor before 0.10.1 are vulnerable to Prototype Pollution due to missing sanitization in set function. **Note:** This vulnerability derives from an incomplete fix in [CVE-2020-7736](https://security.snyk.io/vuln/SNYK-JS-BMOOR-598664). EPSS estimates a 1.63% chance of exploitation in the next 30 days.

Description

The package bmoor before 0.10.1 are vulnerable to Prototype Pollution due to missing sanitization in set function. **Note:** This vulnerability derives from an incomplete fix in [CVE-2020-7736](https://security.snyk.io/vuln/SNYK-JS-BMOOR-598664)

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.63%

73.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-1321

Affected Software

Vendor	Product	Versions
Bmoor Project	Bmoor	< 0.10.1

References

https://github.com/b-heilman/bmoor/commit/29b0162cc1dc1791fc060891f568b0ae29bc542bPatch, Third Party Advisory
https://snyk.io/blog/remediate-javascript-type-confusion-bypassed-input-validation/Third Party Advisory
https://snyk.io/vuln/SNYK-JS-BMOOR-2342622Exploit, Third Party Advisory
https://github.com/b-heilman/bmoor/commit/29b0162cc1dc1791fc060891f568b0ae29bc542bPatch, Third Party Advisory
https://snyk.io/blog/remediate-javascript-type-confusion-bypassed-input-validation/Third Party Advisory
https://snyk.io/vuln/SNYK-JS-BMOOR-2342622Exploit, Third Party Advisory

Timeline

Published: Jan 28, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-23558?

How severe is CVE-2021-23558?

CVE-2021-23558 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.63% probability of exploitation in the next 30 days.

How do I fix CVE-2021-23558?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-23558?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST