CVE-2026-4042
Published: 12 March 2026
Summary
CVE-2026-4042 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Tenda I12 Firmware. Its CVSS base score is 7.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 48.4% of CVEs by exploit likelihood; 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-2026-4042 is a stack-based buffer overflow vulnerability affecting the Tenda i12 router on firmware version 1.0.0.6(2204). The flaw exists in the formWifiMacFilterGet function within the /goform/WifiMacFilterGet file, where manipulation of the 'index' argument triggers the overflow. Published on 2026-03-12, it is associated with CWEs-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), CWE-121 (Stack-based Buffer Overflow), and CWE-787 (Out-of-bounds Write).
The vulnerability enables remote exploitation over the network with low attack complexity and no user interaction required. Exploitation demands low privileges (PR:L) on the target system, potentially allowing an authenticated user with limited access to trigger the buffer overflow. Successful attacks can result in high impacts to confidentiality, integrity, and availability (C:H/I:H/A:H), with a CVSS v3.1 base score of 8.8. A public exploit is available and could be used for attacks.
Advisories and references, including a GitHub issue at https://github.com/Jimi-Lab/cve/issues/2 and multiple VulDB entries (https://vuldb.com/?ctiid.350654, https://vuldb.com/?id.350654, https://vuldb.com/?submit.769463), document the issue, along with the vendor site at https://www.tenda.com.cn/. Specific mitigation or patch details are not outlined in the available description.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-11589
Vulnerability details
A weakness has been identified in Tenda i12 1.0.0.6(2204). The affected element is the function formWifiMacFilterGet of the file /goform/WifiMacFilterGet. This manipulation of the argument index causes stack-based buffer overflow. The attack may be initiated remotely. The exploit has been…
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made available to the public and could be used for attacks.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Stack buffer overflow in router web form handler (authenticated, network-reachable) directly enables remote code execution for privilege escalation (T1068) and exploitation of a public-facing application (T1190).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly addresses the CVE by requiring identification, reporting, and correction of the stack-based buffer overflow flaw in the router firmware.
Requires validation of the 'index' argument in formWifiMacFilterGet to prevent the improper restriction of operations leading to buffer overflow.
Implements memory safeguards like stack canaries or DEP to protect against unauthorized code execution from the stack-based buffer overflow exploitation.