Out of Bounds Write in FreeRTOS-Plus-TCP

published 2025-06-04 17 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-16897

cvss: 7.5; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits: 0; none known

We have identified a buffer overflow issue allowing 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.

Users should upgrade to the latest version and ensure any forked or derivative code is patched to incorporate the new fixes.

Patch / fix

fixed in 1 links 1

Amazon FreeRTOS 4.3.2

github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.3.2 release

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 17 mo ago (2025-06-04)

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	7.5	CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	4.0	7.5	CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

Amazon FreeRTOS

Classification

Weakness

CWE-787 Out-of-bounds Write

References

github.com /FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.3.2
patch
aws.amazon.com /security/security-bulletins/AWS-2025-012/
vendor-advisory
github.com /FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-5x4f-fvv8-wr65
vendor-advisory

Sources

CVE List CVE-2025-5688
NVD CVE-2025-5688

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary