CVE-2026-7426

Description

Insufficient validation of the prefix length field in IPv6 Router Advertisement processing in FreeRTOS-Plus-TCP before V4.2.6 and V4.4.1 allows an adjacent network actor to cause memory corruption by sending a crafted Router Advertisement with a prefix length value exceeding the maximum valid length, resulting in a heap buffer overflow. Users processing IPv4 RA only are not impacted. To mitigate this issue, users should upgrade to the fixed version when available.

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CVSS v3.1 Score

8.1

HIGH

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

EPSS — Exploit Prediction

0.0002

Probability of exploitation

0.06%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
amazon	freertos-plus-tcp	4.0.0 — 4.2.6
amazon	freertos-plus-tcp	4.3.0 — 4.4.1

References

Advisories & Patches

https://aws.amazon.com/security/security-bulletins/2026-023-aws/ https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-97qg-4359-xm3x

Other References

https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1

Frequently Asked Questions

What is CVE-2026-7426? +

Insufficient validation of the prefix length field in IPv6 Router Advertisement processing in FreeRTOS-Plus-TCP before V4.2.6 and V4.4.1 allows an adjacent network actor to cause memory corruption by sending a crafted Router Advertisement with a prefix length value exceeding the maximum valid length, resulting in a heap buffer overflow. Users processing IPv4 RA only are not impacted. To mitigate this issue, users should upgrade to the fixed version when available. It has a CVSS v3.1 base score of 8.1 (HIGH).

How severe is CVE-2026-7426? +

CVE-2026-7426 has a CVSS v3.1 score of 8.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0002, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-7426? +

CVE-2026-7426 affects products from amazon, specifically: freertos-plus-tcp. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-7426? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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