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 breakdown
CVSS 4.0
Attack Vector
Adjacent
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality (Vulnerable System)
None
Integrity (Vulnerable System)
High
Availability (Vulnerable System)
High
Confidentiality (Subsequent System)
None
Integrity (Subsequent System)
None
Availability (Subsequent System)
None
CVSS 3.1
Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High
Affected products
- AWS / FreeRTOS-Plus-TCP4.0.0 – 4.2.6
- AWS / FreeRTOS-Plus-TCP4.3.0 – 4.4.1
- AWS / FreeRTOS-Plus-TCP4.2.6 – 4.2.6
- AWS / FreeRTOS-Plus-TCP4.4.1 – 4.4.1
References
- PATCHhttps://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1
- PATCHhttps://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6
- MISChttps://aws.amazon.com/security/security-bulletins/2026-022-aws/
- VENDOR_ADVISORYhttps://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-wrhm-c99p-2p8g