NVD / CVE Program· CNA icscert

CVE-2021-27504: Texas Instruments FREERTOS Integer Overflow or Wraparound

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.27% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Texas 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.

HighCVSS 7.8 · v3.1—No exploit No fix recorded

Memory safety

BDU:2021-04817

Published: Nov 21, 2023
Updated: Jun 16, 2026
EPSS: 0.2% · 20th percentile
CWE: CWE-190

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.2%

CNA vs NVD score

NVD: 7.8
CNA · icscert: 7.4; 0.4 point gap

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
No fixed version yet

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
amazon	freertos	cpe:2.3:o:amazon:freertos
ti	simplelink cc13xx software development kit	cpe:2.3:a:ti:simplelink_cc13xx_software_development_kit
ti	simplelink cc26xx software development kit	cpe:2.3:a:ti:simplelink_cc26xx_software_development_kit
ti	simplelink cc32xx software development kit	cpe:2.3:a:ti:simplelink_cc32xx_software_development_kit
ti	simplelink msp432e401y	cpe:2.3:a:ti:simplelink_msp432e401y
ti	simplelink msp432e411y	cpe:2.3:a:ti:simplelink_msp432e411y

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

amazon freertos10.4.1
ti simplelink cc13xx software development kitbefore 4.40.00
ti simplelink cc26xx software development kitbefore 4.40.00
ti simplelink cc32xx software development kitbefore 4.10.03
ti simplelink msp432e401yall versions
ti simplelink msp432e411yall versions

Versions reported by the vendor

Affected version ranges reported by the assigning authority (icscert). Independent of NVD's CPE analysis and usually ahead of it.

Texas Instruments CC32XX
- before 4.40.00.07affected
Texas Instruments SimpleLink MSP432E4XX
- all versionsaffected
Texas Instruments SimpleLink-CC13XX
- before 4.40.00affected
Texas Instruments SimpleLink-CC26XX
- before 4.40.00affected
Texas Instruments SimpleLink-CC32XX
- before 4.10.03affected

Same product

amazon: all records

Other highest-scoring records for the same primary product.

CVE-2021-32020The kernel in Amazon Web Services FreeRTOS before 10.4.3 has insufficient bounds checking during management of heap memory.
39Monitor
CVE-2021-31572The kernel in Amazon Web Services FreeRTOS before 10.4.3 has an integer overflow in stream_buffer.c for a stream buffer.
39Monitor
CVE-2021-31571The kernel in Amazon Web Services FreeRTOS before 10.4.3 has an integer overflow in queue.c for queue creation.
39Monitor

Published before and after this one in the same product

← EarlierCVE-2021-43997Nov 17, 2021 · FreeRTOS versions 10.2.0 through 10.4.5 do not prevent non-kernel code from calling the xPortRaisePrivilege internal function to raise privi
31Monitor
Later →CVE-2024-28115Mar 7, 2024 · Privilege Escalation in FreeRTOS Kernel ARMv7-M MPU ports and ARMv8-M ports with MPU support enabled
31Monitor
Later →CVE-2025-5688Jun 4, 2025 · Out of Bounds Write in FreeRTOS-Plus-TCP
30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

David Atch, Omri Ben Bassat, and Tamir ArielMicrosoft Section 52, and the Azure Defender for IoT research group reported these vulnerabilities to CISA.finder

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope