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VulnerabilityPublished Updated

CVE-2025-5688: AWS FreeRTOS · Out-of-bounds Write

Affects AWS FreeRTOSSource CVE Database V5

0

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 12:29 UTC

CVSS 4.0 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Jun 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
GitHubfreertos/FreeRTOS-Plus-TCPpkg:github/freertos/FreeRTOS-Plus-TCPOther threatsAffected
  • =2.3.4
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

  1. Upgrade all affected Amazon FreeRTOS instances to the latest version that includes the patch for CVE-2025-5688.
  2. Audit and patch any forks or derivative FreeRTOS codebases used internally or by third-party vendors to ensure the fix is applied.
  3. Disable LLMNR and mDNS services on devices where these protocols are not required to reduce attack surface.
  4. Implement network segmentation to isolate IoT and embedded devices from critical network segments, limiting local network exposure.
  5. Employ strict network access controls and monitoring to detect anomalous LLMNR/mDNS traffic patterns indicative of exploitation attempts.
  6. Conduct regular firmware and software integrity checks on embedded devices to detect unauthorized modifications.
  7. Collaborate with device manufacturers and suppliers to ensure timely updates and vulnerability management in embedded products.

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.

References

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