CVE-2021-27504
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 · uneditedTexas 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.
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 · moderate confidenceInteger overflow vulnerability in FreeRTOS malloc implementation on Texas Instruments devices. When extremely large values are passed to malloc, the function returns a valid pointer to a small buffer instead of failing, allowing attackers to trigger heap-based buffer overflows and achieve code execution.
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= 10.4.1< 4.40.00< 4.40.00< 4.10.03all versionsall versionsCVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/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 the FreeRTOS version in the firmwareInspect the firmware image or source code for the FreeRTOS version definition, typically found in FreeRTOS.h or version.h. On the device, this may be logged at boot or accessible via debug interfaces.Affected if The installed FreeRTOS version is exactly 10.4.1 (Amazon Freertos)
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Identify the TI Simplelink SDK versionCheck the SDK version string in the development environment, build configuration, or firmware metadata. This is often located in SDK release notes, a version config file, or embedded in the firmware binary.Affected if The TI Simplelink SDK is CC13xx or CC26xx with version < 4.40.00, or CC32xx with version < 4.10.03
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Confirm device is MSP432e401y or MSP432e411yIdentify the exact TI device model from the board marking, firmware identification strings, or MCU part number read via debug probes.Affected if The device model is TI Simplelink MSP432e401y or MSP432e411y (all versions are affected)
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Verify the malloc implementation is presentExamine the firmware binary or source code for the malloc() function implementation. In FreeRTOS, this is typically in heap_1.c through heap_4.c files within the FreeRTOS directory.Affected if The firmware includes the FreeRTOS memory allocator (heap) implementation, which is used when dynamic memory allocation is performed
The environment is affected if it uses Amazon FreeRTOS 10.4.1, or any TI Simplelink SDK version below 4.40.00 for CC13xx/CC26xx, below 4.10.03 for CC32xx, or any version of MSP432e401y/MSP432e411y, with the malloc function present in the firmware.
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.
dbcve · scoped4.10.034.40.00
Apply vendor-supplied patches or firmware updates from Texas Instruments that address the malloc integer overflow; if no patch available, implement input validation bounds checking in malloc to reject oversized allocation requests.
SimpleLink CC13xx/CC26xx SDK >= 4.40.00; SimpleLink CC32xx SDK >= 4.10.03; FreeRTOS to a version later than 10.4.1 (specific version per TI guidance)
- 1. Identify the specific Texas Instruments device and SDK version currently in use from the affected product list (FreeRTOS 10.4.1, SimpleLink CC13xx SDK, SimpleLink CC26xx SDK, SimpleLink CC32xx SDK, or SimpleLink MSP432e401y/MSP432e411y)
- 2. For SimpleLink CC13xx/CC26xx SDK: Upgrade to version 4.40.00 or later
- 3. For SimpleLink CC32xx SDK: Upgrade to version 4.10.03 or later
- 4. For FreeRTOS 10.4.1: Upgrade to a later FreeRTOS version that includes the malloc fix (consult TI's official documentation for the specific fixed FreeRTOS version bundled in the SDK updates
- 5. After upgrading, verify the malloc implementation no longer accepts extremely large values that could cause integer overflow
- 6. Test the device functionality to ensure the upgrade does not break existing functionality
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation6.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA6.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $9,504.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-27504 — 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-2021-27504 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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