How severe is CVE-2021-27433?

CVE-2021-27433 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-2021-27433 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27433?

CVE-2021-27433 affects Arm Mbed Ualloc. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27433?

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-2021-27433 published?

CVE-2021-27433 was published on 2022-05-03 and last updated on 2026-06-17.

CVE-2021-27433

CVE-2021-27433 is a high-severity vulnerability in Arm Mbed Ualloc 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: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Arm Mbed Ualloc
Published: 2022-05-03
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-27433?: 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.
How severe is CVE-2021-27433?: CVE-2021-27433 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-2021-27433 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27433?: CVE-2021-27433 affects Arm Mbed Ualloc. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27433?: 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-2021-27433 published?: CVE-2021-27433 was published on 2022-05-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:arm:mbed_ualloc:1.3.0:*:*:*:*:*:*:*

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