CVE-2021-26706
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThree memory pool creation functions (Mem_PoolCreate, Mem_DynPoolCreate, Mem_DynPoolCreateHW) in Micrium uC/OS uC/LIB calculate pool sizes via multiplication without validating for integer overflow. When provided with sufficiently large arguments, the multiplication wraps around, resulting in an undersized memory allocation that can be exploited.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 1.38.00= 1.38.01= 1.38.02= 1.38.03= 1.38.04= 1.38.05= 1.39.00CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify installed uC/LIB versionLocate the version definition in the Micrium uC/LIB library headers or build artifacts. Check files such as lib.h, lib_cfg.h, or version.h in the include directory of the uC/LIB installation.Affected if The version is 1.38.00, 1.38.01, 1.38.02, 1.38.03, 1.38.04, 1.38.05, or 1.39.00
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Locate the affected memory pool functionsFind the source files containing Mem_PoolCreate, Mem_DynPoolCreate, and Mem_DynPoolCreateHW implementations. These are typically in lib_mem.c or mem.c within the uC/LIB source directory.Affected if These three functions exist in the codebase and the library version is in the affected range.
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Inspect pool size calculation for overflow validationExamine the source code of each affected function to see if there is integer overflow checking before the pool size multiplication operation. Look for bounds validation or overflow detection logic preceding the size calculation.Affected if The code performs multiplication for pool size calculation without first validating that the result will not overflow, allowing wraparound to produce an undersized allocation.
The environment is affected if uC/LIB version is between 1.38.00 and 1.39.00 inclusive and the memory pool creation functions lack integer overflow checks before the size multiplication.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataAdd integer overflow checks before the multiplication operations in all three affected functions to validate that the calculated pool size does not exceed available address space and is within expected bounds.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2021-26706 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-26706 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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