CVE-2026-7423: AWS FreeRTOS-Plus-TCP · Integer Underflow
Affects AWS FreeRTOS-Plus-TCPSource CVE Database V5
Not known to be exploited · CVSS 5.3 Medium : upgrade to 4.4.1 or 4.2.6 when convenient.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.4.1, 4.2.6
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 29 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 30 Oct 2026.
What to do
Upgrade AWS FreeRTOS-Plus-TCP to 4.4.1 or 4.2.6.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| AWSFreeRTOS-Plus-TCP | Affected
| Fixed in
|
| AWSFreeRTOS-Plus-TCP | Affected
| Fixed in
|
GitHubfreertos/FreeRTOS-Plus-TCPpkg:github/freertos/FreeRTOS-Plus-TCPOther threats | Affected
| Fixed in– |
GitHubFreeRTOS-Plus-TCPpkg:github/FreeRTOS-Plus-TCPOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available from AWS in FreeRTOS-Plus-TCP versions 4.4.1 and 4.2.6. Users should upgrade to these fixed versions to remediate the vulnerability. Since this is a cloud service managed by AWS, the vendor handles remediation for the cloud-hosted components. Refer to the AWS security bulletin at https://aws.amazon.com/security/security-bulletins/2026-021-aws/ for official guidance and updates.
Description
Integer underflow in the ICMP and ICMPv6 echo reply handlers in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adjacent network user to cause a denial of service (device crash) when outgoing ping support is enabled, because header sizes are subtracted from a packet length field without validating the field is large enough, resulting in a heap out-of-bounds read of up to approximately 65KB. To mitigate this issue, users should upgrade to the fixed version when available.
References
- github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1 (opens in a new tab)
- github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 (opens in a new tab)
- aws.amazon.com/security/security-bulletins/2026-021-aws/ (opens in a new tab)
- github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-7r59-2pgv-9v2r (opens in a new tab)