CVE-2026-7423

CVE-2026-7423 is a medium-severity vulnerability in Amazon Freertos-plus-tcp with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-191.

Key facts

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-7423?
CVE-2026-7423 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over an adjacent network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-7423 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-7423?
CVE-2026-7423 affects Amazon Freertos-plus-tcp. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-7423?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-7423 have an EU (EUVD) identifier?
Yes. CVE-2026-7423 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26276.
When was CVE-2026-7423 published?
CVE-2026-7423 was published on 2026-04-29 and last updated on 2026-06-17.

References

Affected products (1)

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