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Fencer Vulns
critical 9.8

CVE-2021-26706 json

An issue was discovered in lib_mem.c in Micrium uC/OS uC/LIB 1.38.x and 1.39.00.

published 2022-01-24 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-13496

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 80%
public exploits
0
none known

Summary

An issue was discovered in lib_mem.c in Micrium uC/OS uC/LIB 1.38.x and 1.39.00. The following memory allocation functions do not check for integer overflow when allocating a pool whose size exceeds the address space: Mem_PoolCreate, Mem_DynPoolCreate, and Mem_DynPoolCreateHW. Because these functions use multiplication to calculate the pool sizes, the operation may cause an integer overflow if the arguments are large enough. The resulting memory pool will be smaller than expected and may be exploited by an attacker.

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 9.0

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

Exploit prediction

1.94% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
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

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.