Code execution via allocator size wraparound
Published May 3, 2022 · Updated Apr 16, 2025
Integer wraparound in Arm CMSIS-RTOS2 before 2.1.3 allows attackers to crash devices or execute injected code through crafted allocations. The osRtxMemoryAlloc routine adds metadata and alignment padding to a 32-bit requested size without rejecting arithmetic overflow, so the computed block size can wrap to a smaller value. Reachability requires firmware to pass an attacker-influenced size into the allocator; a successful trigger can corrupt allocation behavior, crash the device, or redirect execution.
Summary
What happened
Integer wraparound in Arm CMSIS-RTOS2 before 2.1.3 allows attackers to crash devices or execute injected code through crafted allocations. The osRtxMemoryAlloc routine adds metadata and alignment padding to a 32-bit requested size without rejecting arithmetic overflow, so the computed block size can wrap to a smaller value. Reachability requires firmware to pass an attacker-influenced size into the allocator; a successful trigger can corrupt allocation behavior, crash the device, or redirect execution.
The record
- CVE
- CVE-2021-27431
- Published
- May 3, 2022
- Updated
- Apr 16, 2025
- Vendor
- Arm
- Product
- CMSIS-RTOS2
- Classifications
- CWE-190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 3, 2022CVE publishedPublication date reported by the CVE source.
- Apr 16, 2025Record updatedLatest update available in the CVE record.
Exploitability
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Is a vulnerable build present?
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- Affected versionversion=unspecified <2.1.3
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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