Vulnerability details

CVE-2026-7424

AWS FreeRTOS-Plus-TCP

Integer Underflow in DHCPv6 Sub-Option Parser in FreeRTOS-Plus-TCP

CVSS 4.0

7.2High

Official description

Integer underflow in the DHCPv6 sub-option parser in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adjacent network actor to corrupt the device's IPv6 address assignment, DNS configuration, and lease times, and to cause a denial of service (permanent IP task freeze requiring hardware reset) by sending a single crafted DHCPv6 packet. The issue is present whenever DHCPv6 is enabled. To mitigate this issue, users should upgrade to version V4.2.6 or V4.4.1 or newer.

CVSS scores

Score	Version	Source	Vector
7.2High	4.0	CVEProject cvelistV5 (CNA) (AMZN)	`CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N`
8.1High	3.1	CVEProject cvelistV5 (CNA) (AMZN)	`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H`

Affected products

Vendor	Product	Versions	Source
AWS	FreeRTOS-Plus-TCP	4.0.0 ≤ v < 4.2.6	CVEProject cvelistV5 (CNA)
AWS	FreeRTOS-Plus-TCP	4.3.0 ≤ v < 4.4.1	CVEProject cvelistV5 (CNA)

References and advisories

https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1 patch
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 patch
https://aws.amazon.com/security/security-bulletins/2026-022-aws/ vendor-advisory
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-wrhm-c99p-2p8g third-party-advisory

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Details

Published: 2026-04-29
Last updated: 2026-04-30
State: Published
Assigner (CNA): AMZN

Exploit prediction (EPSS)

0.22%

Probability of exploitation in 30 days

12.9%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: No
Exploitation: None
Technical impact: Total

Weaknesses (CWE)

CWE-191
Integer Underflow (Wrap or Wraparound)