Raw vector
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-7426 is a medium-severity Out-of-bounds Write (CWE-787) vulnerability in Amazon Freertos-Plus-Tcp. Its CVSS base score is 6.1 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 16th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-7426 is a heap buffer overflow vulnerability stemming from insufficient validation of the prefix length field during IPv6 Router Advertisement (RA) processing in FreeRTOS-Plus-TCP versions before V4.2.6 and V4.4.1. An attacker can trigger the issue by sending a crafted IPv6 RA with a prefix length exceeding the maximum valid value, leading to memory corruption. Systems configured to process only IPv4 RAs are unaffected. The vulnerability is rated with a CVSS v3.1 base score of 8.1 (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H) and maps to CWE-787 (Out-of-bounds Write).
An adjacent network attacker with low complexity and no privileges required can exploit this vulnerability by transmitting a malicious IPv6 RA packet to a vulnerable device. Successful exploitation results in high-impact integrity and availability disruptions through heap memory corruption, though confidentiality is not affected. The attack requires adjacency on the local network (AV:A), making it feasible in scenarios like shared wireless networks or misconfigured LAN segments where the target processes IPv6 RAs.
Advisories recommend upgrading to FreeRTOS-Plus-TCP V4.2.6 or V4.4.1, which address the validation flaw. Relevant resources include the AWS security bulletin at https://aws.amazon.com/security/security-bulletins/2026-023-aws/, GitHub release tags for the fixed versions at https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 and https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1, and the GitHub security advisory at https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-97qg-4359-xm3x.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-26284
Vulnerability Data
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (including fuzzing and bounds checks) finds out-of-bounds write flaws before deployment.
Requiring documented secure-development standards and tools can mandate bounds-checked coding practices that avoid the weakness.
Input validation can structurally reject or sanitize data that would otherwise trigger an out-of-bounds write.
Memory-protection mechanisms limit the exploitability and blast radius of a successful out-of-bounds write.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.
Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.
Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development and acceptance can detect and prevent out-of-bounds write defects.
Secure development life cycle mandates practices that prevent out-of-bounds writes.
Application security requirements can specify bounds-checking and safe memory handling.
Secure architecture and engineering principles reduce the likelihood of buffer overflows.
Secure coding directly addresses out-of-bounds writes through language choice and coding standards.
Change management can enforce review gates that catch unsafe memory operations before deployment.