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Out of Bounds Write (CWE-787) in FreeRTOS-Plus-TCP

High
aggarg published GHSA-5x4f-fvv8-wr65 Jun 4, 2025

Package

FreeRTOS-Plus-TCP

Affected versions

See Advisory

Patched versions

4.3.2

Description

Summary

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:

  1. Buffer Allocation Scheme 1 - Allocates buffers from a pre-defined pool of fixed-size buffers.
  2. Buffer Allocation Scheme 2 - Allocates buffers of required size dynamically from the heap.

An issue exists where, under certain circumstances, a buffer overflow in FreeRTOS-Plus-TCP may allow out-of-bounds write.

Impact

A buffer overflow issue 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.

Impacted versions

  • 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.

Patches

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

NA.

References

If you have any questions or comments about this advisory, we ask that you contact AWS Security via our vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVE ID

CVE-2025-5688

Weaknesses

Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer. Learn more on MITRE.

Credits