CVE-2026-7423

Integer Underflow in ICMP Echo Reply Processing in FreeRTOS-Plus-TCP

MEDIUM
6.5
CVSS Score
Published: April 29, 2026 at 06:36 PM UTC
Updated: October 26, 2026 at 08:10 PM UTC
3 products affected across 3 vendorsFreertos Plus TCPFreeRTOS-Plus-TCPFreeRTOS-Plus-TCP

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

4.0.0 ≤ v < 4.2.64.3.0 ≤ v < 4.4.1
4.0.0 ≤ v < 4.2.64.3.0 ≤ v < 4.4.14.0.04.3.0
Vendor states this is fixed in 4.2.6 (unaffected)
Vendor states this is fixed in 4.4.1 (unaffected)

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-191

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