CVE-2021-27431

highpriority · track · 39EPSS 0.011 · 67 %ileEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

1.15% (67th) EPSS

CVSS 7.5 · high

Is it mine?

58 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · cisa_csaf_ot

EPSS · scored 2026-10-27

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.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

No vendor fix yet; a mitigation is available.

MitigationARM CMSIS-RTOS2cisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationARM Mbed OScisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationARM mbed-ualloccisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationAmazon FreeRTOScisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationApache Nuttx OScisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationBlackBerry QNX OS for Medicalcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationBlackBerry QNX OS for Safetycisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationBlackBerry QNX SDPcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationCesanta Software Mongoose OScisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationGoogle Cloud IoT Device SDKcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationMedia Tek LinkIt SDKcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationMicrium OScisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationMicrium uC/OScisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationNXP MCUXpresso SDKcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationNXP MQXcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationRIOT OScisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationRedhat newlibcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationSamsung Tizen RT RTOScisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationTencentOS-tinycisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationTexas Instruments CC32XXcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationTexas Instruments SimpleLinkcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationTexas Instruments SimpleLink-CC13XXcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationTexas Instruments SimpleLink-CC26XXcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationTexas Instruments SimpleLink-CC32XXcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationUclibc-NGcisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationWindriver VxWorkscisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationZephyr Project RTOScisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr
MitigationeCosCentric eCosPro RTOScisa_csaf_ot
Zephyr Project: Update to 2.5 or later. Patches available for prior supported versions. See the Zephyr security advisory for more information.
https://github.com/zephyrproject-rtos/zephyr

cvss

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.3–9.8

v2.07.5highAV:N/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 10 · impact 6.4

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 5.9

v3.07.3highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:Lsecondary · CISA US

v3.17.3highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:Lsecondary · ENISA EU

v3.17.3highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:Lsecondary · ics-cert@hq.dhs.gov USexploitability 3.9 · impact 3.4

v3.19criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-190USCWE-190US

affected products (58)

Products and version ranges known to be affected.

ARM CMSIS-RTOS2: versions prior to 2.1.3all versionscisa_csaf_otUS
ARM Mbed OS: Version 6.3.0all versionscisa_csaf_otUS
ARM mbed-ualloc: Version 1.3.0all versionscisa_csaf_otUS
Amazon FreeRTOS: Version 10.4.1all versionscisa_csaf_otUS
Apache Nuttx OS: Version 9.1.0all versionscisa_csaf_otUS
BlackBerry QNX OS for Medical: Versions 1.1 and earlier safety products compliant with IEC 62304all versionscisa_csaf_otUS
BlackBerry QNX OS for Safety: Versions 1.0.1 and earlier safety products compliant with IEC 61508 and/or ISO 26262all versionscisa_csaf_otUS
BlackBerry QNX SDP: Versions 6.5.0 SP1 and earlierall versionscisa_csaf_otUS
Cesanta Software Mongoose OS: v2.17.0all versionscisa_csaf_otUS
Google Cloud IoT Device SDK: Version 1.0.2all versionscisa_csaf_otUS
Media Tek LinkIt SDK: versions prior to 4.6.1all versionscisa_csaf_otUS
Micrium OS: Versions 5.10.1 and priorall versionscisa_csaf_otUS
Micrium uC/OS: uC/LIB Versions 1.38.xx Version 1.39.00all versionscisa_csaf_otUS
NXP MCUXpresso SDK: versions prior to 2.8.2all versionscisa_csaf_otUS
NXP MQX: Versions 5.1 and priorall versionscisa_csaf_otUS
RIOT OS: Version 2020.01.1all versionscisa_csaf_otUS
Redhat newlib: versions prior to 4.0.0all versionscisa_csaf_otUS
Samsung Tizen RT RTOS: versions prior 3.0.GBBall versionscisa_csaf_otUS
TencentOS-tiny: Version 3.1.0all versionscisa_csaf_otUS
Texas Instruments CC32XX: versions prior to 4.40.00.07all versionscisa_csaf_otUS

showing 20 of 58

advisories (1)

Vendor and ecosystem advisories describing this.

ICSA-21-119-04Multiple RTOS (Update E)2021-04-29icsa · cisa_csaf_otUS
Successful exploitation of these vulnerabilities could result in unexpected behavior such as a crash or a remote code injection/execution.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cisa_csaf_ot NVD CVE.org MITRE

published 2022-05-03modified 2026-06-17

references (7)

External citations — patches, advisories, analysis.

scry

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