Is CVE-2026-77236 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-77236 being exploited in the wild.

How severe is CVE-2026-77236?

High severity, with a CVSS score of 7.3, published 21 August 2026.

Which products and versions are affected?

FreeRTOS FreeRTOS-Kernel before 11.3.1.

Is there a fix for CVE-2026-77236?

A patch was published on 2026-08-21: Version 11.3.1 released with validation added to SecureContext_AllocateContext Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-77236 attacked?

It is attacked with local access, in a software library.

Am I affected by CVE-2026-77236?

Check whether you run Amazon Freertos. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-77236: FreeRTOS-Kernel secure context allocation missing size validation

CVE-2026-77236 · Severity: high · CVSS 7.3 · Published 2026-08-21

FreeRTOS-Kernel is a real-time operating system kernel used in embedded systems and IoT devices. A validation flaw in secure context memory allocation allows local attackers to corrupt secure-world heap metadata through an undersized stack parameter, potentially compromising the integrity of security-critical operations and sensitive data in TrustZone environments.

Technologies: Amazon Freertos. Vendors: Amazon.

Quick answers

Is CVE-2026-77236 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-77236 being exploited in the wild.
How severe is CVE-2026-77236?: High severity, with a CVSS score of 7.3, published 21 August 2026.
Which products and versions are affected?: FreeRTOS FreeRTOS-Kernel before 11.3.1.
Is there a fix for CVE-2026-77236?: A patch was published on 2026-08-21: Version 11.3.1 released with validation added to SecureContext_AllocateContext Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-77236 attacked?: It is attacked with local access, in a software library.
Am I affected by CVE-2026-77236?: Check whether you run Amazon Freertos. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability is an input validation flaw in the SecureContext_AllocateContext function within ARMv8-M secure-side ports. When allocating secure context memory, the function fails to validate that the requested stack size meets a minimum threshold (the stack seal size), allowing an attacker with local access to supply an undersized stack parameter. This results in an out-of-bounds write that corrupts secure-world heap metadata. The vulnerability affects FreeRTOS-Kernel versions before 11.3.1. The fix adds validation to ensure the secure stack size plus seal size does not overflow before allocation, and rejects stack sizes smaller than the seal size.

Affected products

FreeRTOS FreeRTOS-Kernel before 11.3.1

Timeline

2026-08-21: disclosed
2026-08-21: patched: Version 11.3.1 released with validation added to SecureContext_AllocateContext

References

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