CVE-2025-5688: amazon freertos Out-of-bounds Write
Vulnerability summary
CVE-2025-5688 is a high (CVSS 7.5) Out-of-bounds Write vulnerability in amazon freertos. EPSS estimates a 0.35% chance of exploitation in the next 30 days, higher than 27% of scored vulnerabilities.
Timeline
- 04-06-2025PublishedVulnerability first disclosed.
- 14-10-2025Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST7.5HighCVSS: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
EPSS trend
Probability
0.35%
Chance of exploitation in the next 30 days
Percentile
27%
Versus all other CVEs
30-day change
0.00 pp
From 0.35% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Amazon1 product
- freertos≥ 2.3.4, < 4.3.2
1 vendor · 1 product
References
3 links- aws.amazon.com/security/security-bulletins/AWS-2025-012/Vendor Advisory