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.

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Exploitation none

Automatable no

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
AWS FreeRTOS-Plus-TCP unaffected
Version Status Constraints
4.0.0 affected < 4.2.6
4.3.0 affected < 4.4.1
4.2.6 unaffected —
4.4.1 unaffected —

No data.

No data.

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Project Subscriptions

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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://aws.amazon.com/security/security-bulletins/2026-023-aws/ cve-icon cve-icon
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 cve-icon cve-icon
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1 cve-icon cve-icon
History

Wed, 29 Apr 2026 20:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 29 Apr 2026 19:30:00 +0000

Type Values Removed Values Added
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.
Title Out-of-Bounds Write via Unsanitized Prefix Length in Router Advertisement Processing in FreeRTOS-Plus-TCP
Weaknesses CWE-787
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H'}

cvssV4_0

{'score': 6.1, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: AMZN

Published:

Updated: 2026-04-29T19:33:24.116Z

Reserved: 2026-04-29T14:27:53.201Z

Link: CVE-2026-7426

cve-icon Vulnrichment

Updated: 2026-04-29T19:33:08.227Z

cve-icon NVD

Status : Received

Published: 2026-04-29T20:16:32.143

Modified: 2026-04-29T20:16:32.143

Link: CVE-2026-7426

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-04-29T21:15:16Z

Weaknesses