CVE-2021-27433

Name: CVE-2021-27433
Creator: NVD / NIST
Published: 2022-05-03T21:15:08.57+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.55%

Last modified Jun 17, 2026

CVE-2021-27433 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. ARM mbed-ualloc memory library version 1.3.0 is vulnerable to integer wrap-around in function mbed_krbs, which can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or a remote code injection/execution.. EPSS estimates a 1.55% chance of exploitation in the next 30 days.

Description

ARM mbed-ualloc memory library version 1.3.0 is vulnerable to integer wrap-around in function mbed_krbs, which can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or a remote code injection/execution.

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

1.55%

72.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Arm	Mbed Ualloc	1.3.0

References

https://github.com/ARMmbed/mbed-os/pull/14408Issue Tracking, Patch, Third Party Advisory
https://www.cisa.gov/uscert/ics/advisories/icsa-21-119-04Third Party Advisory, US Government Resource
https://github.com/ARMmbed/mbed-os/pull/14408Issue Tracking, Patch, Third Party Advisory
https://www.cisa.gov/uscert/ics/advisories/icsa-21-119-04Third Party Advisory, US Government Resource

Timeline

Published: May 3, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-27433?

How severe is CVE-2021-27433?

CVE-2021-27433 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.55% probability of exploitation in the next 30 days.

How do I fix CVE-2021-27433?

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-2021-27433?

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

Scan your code now

Source: NVD / NIST