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Fencer Vulns
high 7.3

CVE-2021-27435 json

ARM mbed Integer Overflow or Wraparound

published 2022-05-03 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-14189

cvss
7.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

ARM mbed product Version 6.3.0 is vulnerable to integer wrap-around in malloc_wrapper function, which can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or a remote code injection/execution.

Patch / fix

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-119-04 updated cvss 7.3

Multiple RTOS (Update E)

  • multiple Amazon FreeRTOS 10.4.1 multiple Apache Nuttx OS 9.1.0 multiple ARM CMSIS-RTOS2 < 2.1.3 multiple ARM Mbed OS 6.3.0 multiple ARM mbed-ualloc 1.3.0 multiple BlackBerry QNX OS for Medical <= 1.1
    +22 more products
    multiple BlackBerry QNX OS for Safety <= 1.0.1 multiple BlackBerry QNX SDP <= 6.5.0 SP1 multiple Cesanta Software Mongoose OS 2.17.0 multiple eCosCentric eCosPro RTOS >= 2.0.1, <= 4.5.3 multiple Google Cloud IoT Device SDK 1.0.2 multiple Media Tek LinkIt SDK < 4.6.1 multiple Micrium OS <= 5.10.1 multiple Micrium uC/OS 1.38.xx, 1.39.00 multiple NXP MCUXpresso SDK < 2.8.2 multiple NXP MQX <= 5.1 multiple Redhat newlib < 4.0.0 multiple RIOT OS 2020.01.1 multiple Samsung Tizen RT RTOS < 3.0.GBB multiple TencentOS-tiny 3.1.0 multiple Texas Instruments CC32XX < 4.40.00.07 multiple Texas Instruments SimpleLink MSP432E4XX multiple Texas Instruments SimpleLink-CC13XX < 4.40.00 multiple Texas Instruments SimpleLink-CC26XX < 4.40.00 multiple Texas Instruments SimpleLink-CC32XX < 4.10.03 multiple Uclibc-NG < 1.0.36 multiple Windriver VxWorks < 7.0 multiple Zephyr Project RTOS < 2.5
    affected: mitigation “Hitachi Energy GMS600 - See public advisory.” search.abb.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
18 mo ago

Exploit prediction

1.86% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/ARMmbed/mbed-os/pull/14408 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • ARM mbed

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.