How severe is CVE-2021-27431?

CVE-2021-27431 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2021-27431 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27431?

CVE-2021-27431 affects Arm Cmsis-rtos. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27431?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-27431 published?

CVE-2021-27431 was published on 2022-05-03 and last updated on 2026-06-17.

CVE-2021-27431

CVE-2021-27431 is a high-severity vulnerability in Arm Cmsis-rtos with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-190.

Key facts

Severity: High (CVSS 3.x base score 7.3)
CVSS v2: 7.5
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Arm Cmsis-rtos
Published: 2022-05-03
Last modified: 2026-06-17

Description

ARM CMSIS RTOS2 versions prior to 2.1.3 are vulnerable to integer wrap-around inosRtxMemoryAlloc (local malloc equivalent) function, which can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or injected code execution.

Frequently asked questions

What is CVE-2021-27431?: ARM CMSIS RTOS2 versions prior to 2.1.3 are vulnerable to integer wrap-around inosRtxMemoryAlloc (local malloc equivalent) function, which can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or injected code execution.
How severe is CVE-2021-27431?: CVE-2021-27431 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2021-27431 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27431?: CVE-2021-27431 affects Arm Cmsis-rtos. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27431?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-27431 published?: CVE-2021-27431 was published on 2022-05-03 and last updated on 2026-06-17.

References

https://www.cisa.gov/uscert/ics/advisories/icsa-21-119-04

Affected products (1)

cpe:2.3:o:arm:cmsis-rtos:*:*:*:*:*:*:*:*

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