Integer overflow in Amazon Freertos-Plus-Tcp
CVE-2026-7423
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (27.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 27.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.001
Affected products
- Amazon Freertos-Plus-Tcp
- AWS Freertos-Plus-Tcp — versions 4.0.0, 4.3.0, 4.2.6
Weakness classification (CWE)
References
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (vendor-advisory, Vendor Advisory)
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (patch, Release Notes)
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (patch, Release Notes)
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (Patch, third-party-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-7423?
- CVE-2026-7423 is a medium-severity vulnerability in Amazon Freertos-Plus-Tcp, classified under Integer Underflow. CVSS score: 5.3/10. Published 2026-04-29.
- How severe is CVE-2026-7423?
- Medium severity. CVSS v3 base score is 5.3 out of 10.