CVE-2025-5688
Out of Bounds Write in FreeRTOS-Plus-TCP
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Out of Bounds Write in FreeRTOS-Plus-TCP
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.
- Record
CVE-2025-5688- CVSS 4.0
- 7.5 High
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 - Weakness
- CWE-787
- Updated
- 2026-11-02
EUVDEUVD-2025-16897
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.
- Record
EUVD-2025-16897- CVSS 4.0
- 7.5 High
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 - Updated
- 2026-11-02
NVD
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.
- Record
CVE-2025-5688- CVSS 4.0
- 7.5 High
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 - Weakness
- CWE-787
- Updated
- 2026-11-02
OSV
Out of Bounds Write in FreeRTOS-Plus-TCP
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.
- Record
CVE-2025-5688- CVSS 4.0
- 7.5 High
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 - Weakness
- CWE-787
- Updated
- 2026-11-02
Affected products
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | mbanyamer/CVE-2025-5688-FreeRTOS-Plus-TCP-Out-of-Bounds-Write | 2026-02-26 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-5688 is a high vulnerability (CVSS 7.5) in Amazon Freertos, published June 4, 2025. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 0.35%, the 28th percentile. No source names a fixed version.
References
aws.amazon.com/security/security-bulletins/AWS-2025-012
github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.3.2
nvd.nist.gov/vuln/detail/CVE-2025-5688