CVE-2026-5608
Published: 06 April 2026
Summary
CVE-2026-5608 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Belkin F9K1122 Firmware. Its CVSS base score is 7.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 49.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Deeper analysis
CVE-2026-5608 is a stack-based buffer overflow vulnerability affecting the Belkin F9K1122 router on firmware version 1.00.33. The flaw exists in the formWlanSetup function of the /goform/formWlanSetup file, triggered by manipulation of the "webpage" argument. It is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-121 (Stack-based Buffer Overflow), with a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
The vulnerability enables remote exploitation by an attacker possessing low privileges, such as an authenticated user on the device. Successful exploitation can result in high impacts to confidentiality, integrity, and availability, potentially allowing arbitrary code execution and full device compromise. A public exploit is available for use.
Advisories and details are documented in references including VulDB entries and a GitHub repository. The vendor was contacted early regarding disclosure but has not responded or provided patches or mitigations.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-19146
Vulnerability details
A vulnerability was detected in Belkin F9K1122 1.00.33. Affected is the function formWlanSetup of the file /goform/formWlanSetup. The manipulation of the argument webpage results in stack-based buffer overflow. The attack may be performed from remote. The exploit is now public…
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and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Stack-based buffer overflow in router web interface form handler enables remote authenticated RCE and full device compromise, directly mapping to exploitation of public-facing application and exploitation for privilege escalation.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly prevents stack-based buffer overflow by validating and sanitizing the 'webpage' argument in the formWlanSetup function.
Implements memory protections such as stack canaries and ASLR to block or detect exploitation of the stack-based buffer overflow.
Requires timely patching or firmware updates to remediate the specific buffer overflow vulnerability in Belkin F9K1122 firmware 1.00.33.