Scope: AWS
Content Type: Important (requires attention)
Publication Date: 2025/06/04 10:00 AM PDT
Description
FreeRTOS-Plus-TCP is an open source TCP/IP stack implementation specifically designed for FreeRTOS. The stack provides a standard Berkeley sockets interface and supports essential networking protocols including IPv6, ARP, DHCP, DNS, LLMNR, mDNS, NBNS, RA, ND, ICMP, and ICMPv6. FreeRTOS-Plus-TCP offers two Buffer Allocation Schemes for buffer management:
- Buffer Allocation Scheme 1 - Allocates buffers from a pre-defined pool of fixed-size buffers.
- Buffer Allocation Scheme 2 - Allocates buffers of required size dynamically from the heap.
We identified CVE-2025-5688, that may allow out-of-bounds write when processing LLMNR or mDNS queries with very long DNS names. This issue only affects systems using Buffer Allocation Scheme 1 with LLMNR or mDNS enabled.
Affected version:
- v2.3.4 through v4.3.1, if LLMNR is used with Buffer Allocation Scheme 1.
- v4.0.0 through v4.3.1, if mDNS is used with Buffer Allocation Scheme 1.
Resolution:
This issue has been addressed in FreeRTOS-Plus-TCP version 4.3.2. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.
Workarounds:
None.
References:
Acknowledgement:
We would like to thank Purdue University for collaborating on this issue through the coordinated vulnerability disclosure process.
Please email aws-security@amazon.com with any security questions or concerns.