CVE-2026-2067: UTT 520W Firmware Buffer Overflow Flaw

CVE-2026-2067 Overview

CVE-2026-2067 is a buffer overflow vulnerability in the UTT 进取 520W router running firmware version 1.7.7-180627. The flaw resides in the strcpy call within the /goform/formTimeGroupConfig handler. Attackers can trigger memory corruption by supplying an oversized value to the year1 argument. The attack is remotely exploitable and requires only low-privileged access. The exploit has been publicly disclosed, and the vendor did not respond to disclosure attempts, leaving affected devices without an official patch.

Critical Impact

Remote attackers with low-privileged access can corrupt router memory through the year1 parameter, potentially achieving arbitrary code execution on the device and full compromise of network perimeter functions.

Affected Products

• UTT 520W Firmware version 1.7.7-180627
• UTT 520W hardware appliance
• UTT 进取 (Jinqu) 520W router series

Discovery Timeline

• 2026-02-06 - CVE-2026-2067 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2026-2067

Vulnerability Analysis

The vulnerability is a classic stack-based buffer overflow [CWE-119] in the web management interface of the UTT 520W router. The HTTP handler bound to /goform/formTimeGroupConfig accepts a year1 request parameter and copies it into a fixed-size stack buffer using the unsafe strcpy function. Because strcpy does not enforce destination bounds, an attacker-supplied year1 value exceeding the buffer length overwrites adjacent stack memory, including saved return addresses. This class of router firmware vulnerability typically enables arbitrary code execution on the MIPS or ARM SoC running the device's web service. According to the disclosure, the vendor was contacted but did not respond, so no official fix exists.

Root Cause

The root cause is the use of strcpy without length validation on attacker-controlled input from the year1 HTTP parameter in /goform/formTimeGroupConfig. The handler trusts the request data and copies it directly into a stack-allocated buffer of fixed size. Combined with the absence of stack canaries and address space layout randomization typical of low-cost router firmware, this enables reliable exploitation.

Attack Vector

Exploitation requires network reachability to the router's web management interface and authenticated access at the operator level. An attacker submits a crafted POST request to /goform/formTimeGroupConfig with an oversized year1 parameter value. The overflow overwrites the saved return address on the stack, redirecting execution to attacker-controlled data or shellcode. Successful exploitation grants control over the router's HTTP service process and, given the typical privilege model of embedded routers, control of the device.

The vulnerability mechanism is documented in the public proof-of-concept at the GitHub CVE Details and VulDB #344634 entries.

Detection Methods for CVE-2026-2067

Indicators of Compromise

• HTTP POST requests to /goform/formTimeGroupConfig containing unusually long year1 parameter values, typically exceeding 64 bytes.
• Unexpected reboots or web service crashes on UTT 520W devices coinciding with inbound management-interface traffic.
• New or unauthorized administrative sessions following anomalous traffic to the router management port.
• Outbound connections from the router to unknown infrastructure, indicating post-exploitation implant activity.

Detection Strategies

• Inspect web application firewall and IDS logs for POST bodies to /goform/formTimeGroupConfig where the year1 field length exceeds expected date string bounds.
• Apply pattern-matching rules that flag binary or non-printable characters in date-related router configuration parameters.
• Correlate router syslog entries showing HTTP daemon restarts with preceding management-plane HTTP traffic.

Monitoring Recommendations

• Forward router syslog and HTTP access logs to a centralized logging platform and alert on /goform/ endpoint anomalies.
• Monitor for management interfaces (HTTP/HTTPS) exposed on WAN-facing interfaces using external attack surface scans.
• Baseline expected administrative source IPs and alert on management-plane access from unexpected networks.

How to Mitigate CVE-2026-2067

Immediate Actions Required

• Restrict access to the UTT 520W web management interface to trusted administrative VLANs only, blocking WAN-side exposure.
• Rotate administrator credentials and disable any unused operator-level accounts that could be leveraged for the authenticated attack path.
• Place affected devices behind an upstream firewall or reverse proxy capable of filtering oversized HTTP parameters.
• Evaluate replacement of the UTT 520W given the vendor's lack of response to disclosure.

Patch Information

No vendor patch is available. According to the public disclosure, UTT was contacted prior to publication but did not respond. Affected operators should monitor the VulDB advisory for updates and assume the firmware will remain unpatched.

Workarounds

• Disable remote management on the WAN interface and limit HTTP administration to a dedicated management subnet.
• Deploy an inline web application firewall rule that drops requests to /goform/formTimeGroupConfig where the year1 parameter exceeds a strict length such as 16 bytes.
• Segment the router's management plane behind a jump host requiring multi-factor authentication.
• Plan migration to a vendor that provides active firmware support and a documented vulnerability response process.

# Example WAF rule to drop oversized year1 values (ModSecurity syntax)
SecRule REQUEST_URI "@streq /goform/formTimeGroupConfig" \
    "id:1002067,phase:2,deny,status:400,\
    chain,msg:'CVE-2026-2067 buffer overflow attempt'"
    SecRule ARGS:year1 "@gt 16" "t:length"