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CVE-2026-7426

Out-of-Bounds Write via Unsanitized Prefix Length in Router Advertisement Processing in FreeRTOS-Plus-TCP

HIGH
8.1
CVSS Score
Published: April 29, 2026 at 06:53 PM UTC
Updated: October 26, 2026 at 08:10 PM UTC
3 products affected across 3 vendorsFreertos Plus TCPFreeRTOS-Plus-TCPFreeRTOS-Plus-TCP

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Severity
HIGH8.1
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Freertos Plus TCP· Amazon
95%
4.0.0 ≤ v < 4.2.64.3.0 ≤ v < 4.4.1
Affected range stops below 4.2.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.4.1, so it looks safe — our inference, not a vendor statement
FreeRTOS-Plus-TCP· AWS
90%
4.0.0 ≤ v < 4.2.64.3.0 ≤ v < 4.4.14.0.04.3.0
Vendor states this is fixed in 4.2.6 (unaffected)
Vendor states this is fixed in 4.4.1 (unaffected)
FreeRTOS-Plus-TCP· Freertos
85%
All versions

References (4)

PatchRelease Notes
Source: cverecord
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1
PatchRelease Notes
Source: cverecord
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6
Vendor Advisory
Source: cverecord
https://aws.amazon.com/security/security-bulletins/2026-023-aws/
Third Party AdvisoryPatchVendor Advisory
Source: cverecord
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-97qg-4359-xm3x

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHAMZN
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-787

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