CVE-2026-0839
Published: 11 January 2026
Summary
CVE-2026-0839 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Utt 520W Firmware. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 11.0th 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).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly mitigates the buffer overflow by requiring validation of the wepkey1 input argument to ensure it does not exceed buffer bounds.
Provides memory protections like ASLR, DEP, and stack canaries that prevent successful exploitation of the strcpy buffer overflow for arbitrary code execution.
Mandates timely flaw remediation, such as firmware patching or device replacement, to address the unpatched buffer overflow vulnerability.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Buffer overflow in router web form (/goform/APSecurity) directly enables remote exploitation of a public-facing application, leading to arbitrary code execution.
NVD Description
A weakness has been identified in UTT 进取 520W 1.7.7-180627. Affected is the function strcpy of the file /goform/APSecurity. Executing a manipulation of the argument wepkey1 can lead to buffer overflow. The attack may be performed from remote. The exploit…
more
has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.
Deeper analysisAI
CVE-2026-0839 is a buffer overflow vulnerability affecting the UTT 进取 520W router running firmware version 1.7.7-180627. The issue resides in the strcpy function within the /goform/APSecurity file, where manipulation of the wepkey1 argument triggers the overflow. Published on January 11, 2026, it is associated with CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-120 (Buffer Copy without Checking Size of Input), earning 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 can be exploited remotely by an attacker with low privileges (PR:L), requiring no user interaction. Successful exploitation allows high-impact compromise of confidentiality, integrity, and availability, potentially enabling arbitrary code execution on the affected device. A public exploit is available, increasing the risk of attacks against exposed UTT 进取 520W instances.
Advisories from VulDB indicate the vendor was notified early but provided no response or patch. Security practitioners should reference VulDB entries (ctiid.340439, id.340439, submit.729028) and the GitHub repository at https://github.com/GUOTINGTING2297/cve/blob/main/1234/29.md for additional details, isolating or replacing affected devices until mitigation is confirmed.
Exploits are publicly disclosed, heightening the urgency for scanning and remediation in environments using the UTT 进取 520W 1.7.7-180627 firmware.
Details
- CWE(s)