How severe is CVE-2026-7426?

CVE-2026-7426 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2026-7426 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-7426?

CVE-2026-7426 affects Amazon Freertos-plus-tcp. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-7426?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-7426 have an EU (EUVD) identifier?

Yes. CVE-2026-7426 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26284.

When was CVE-2026-7426 published?

CVE-2026-7426 was published on 2026-04-29 and last updated on 2026-06-17.

CVE-2026-7426

CVE-2026-7426 is a high-severity vulnerability in Amazon Freertos-plus-tcp with a CVSS 3.x base score of 8.1. 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-787.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v4: 6.1
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-26284
Weakness: CWE-787
Affected product: Amazon Freertos-plus-tcp
Published: 2026-04-29
Last modified: 2026-06-17

Description

Insufficient validation of the prefix length field in IPv6 Router Advertisement processing in FreeRTOS-Plus-TCP before V4.2.6 and V4.4.1 allows an adjacent network actor to cause memory corruption by sending a crafted Router Advertisement with a prefix length value exceeding the maximum valid length, resulting in a heap buffer overflow. Users processing IPv4 RA only are not impacted. To mitigate this issue, users should upgrade to the fixed version when available.

Frequently asked questions

What is CVE-2026-7426?: Insufficient validation of the prefix length field in IPv6 Router Advertisement processing in FreeRTOS-Plus-TCP before V4.2.6 and V4.4.1 allows an adjacent network actor to cause memory corruption by sending a crafted Router Advertisement with a prefix length value exceeding the maximum valid length, resulting in a heap buffer overflow. Users processing IPv4 RA only are not impacted. To mitigate this issue, users should upgrade to the fixed version when available.
How severe is CVE-2026-7426?: CVE-2026-7426 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2026-7426 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-7426?: CVE-2026-7426 affects Amazon Freertos-plus-tcp. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-7426?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-7426 have an EU (EUVD) identifier?: Yes. CVE-2026-7426 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26284.
When was CVE-2026-7426 published?: CVE-2026-7426 was published on 2026-04-29 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:amazon:freertos-plus-tcp:*:*:*:*:*:*:*:*

More vulnerabilities in Amazon Freertos-plus-tcp

CVE-2024-38373 — Critical (CVSS 9.6): FreeRTOS-Plus-TCP is a lightweight TCP/IP stack for FreeRTOS. FreeRTOS-Plus-TCP versions 4.0.0 through 4.1.0 contain a…
CVE-2026-7424 — High (CVSS 8.1): Integer underflow in the DHCPv6 sub-option parser in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adjacent…
CVE-2026-7425 — Medium (CVSS 6.5): Insufficient option length validation in the IPv6 Router Advertisement parser in FreeRTOS-Plus-TCP before V4.2.6 and…
CVE-2026-7422 — Medium (CVSS 6.5): Insufficient packet validation in FreeRTOS-Plus-TCP before V4.2.6 and V4.4.1 allows an adjacent network actor to bypass…
CVE-2025-11617 — Medium (CVSS 5.4): A missing validation check in FreeRTOS-Plus-TCP's IPv6 packet processing code can lead to an out-of-bounds read when…
CVE-2025-11616 — Medium (CVSS 5.4): A missing validation check in FreeRTOS-Plus-TCP's ICMPv6 packet processing code can lead to an out-of-bounds read when…

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