CVE-2021-27504

highpriority · track · 31EPSS 0.003 · 20 %ileDEEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.28% (20th) EPSS

CVSS 7.8 · high

Is it mine?

73 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · cisa_csaf_ot

EPSS · scored 2026-10-27

Texas Instruments devices running FREERTOS, malloc returns a valid pointer to a small buffer on extremely large values, which can trigger an integer overflow vulnerability in 'malloc' for FreeRTOS, resulting in 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.

7.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.5–7.8

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 1.8 · impact 5.9

v3.06.5mediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:Hsecondary · CISA US

v3.17.4highAV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.17.4highCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.17.4highCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · ics-cert@hq.dhs.gov USexploitability 1.4 · impact 5.9

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · SICK PSIRT DE

v3.17.1highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-190USprimaryCWE-190USCWE-190USCWE-190US

affected products (73)

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 73

advisories (2)

Vendor and ecosystem advisories describing this.

SCA-2024-0004Third party vulnerabilities in SICK CDE-1002024-11-07csaf · sick_psirtDE
The SICK CDE-100 uses the open-source libraries FreeRTOS, lwIP and MCU Boot. The used libraries contain vulnerabilities that affect the SICK CDE-100.
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 (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cisa_csaf_ot sick_psirt NVD CVE.org MITRE

published 2023-11-21modified 2026-06-17

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+4649 more

references (9)

External citations — patches, advisories, analysis.

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