CVE-2026-14721: UTT HiPER 1250GW Buffer Overflow Flaw

CVE-2026-14721 Overview

CVE-2026-14721 is a stack-based buffer overflow vulnerability in the UTT HiPER 1250GW router, affecting firmware versions up to 3.2.7-210907-180535. The flaw resides in an unknown function within the /goform/ConfigWirelessBase_5g handler of the Web Endpoint component. Attackers can trigger the overflow by manipulating the ssid argument in a crafted request. The issue is classified under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer). The exploit details have been publicly disclosed, increasing the risk of opportunistic exploitation against exposed devices. Remote exploitation is possible, though the attacker must hold low-level privileges on the target.

Critical Impact
Authenticated remote attackers can corrupt stack memory on the router, potentially leading to arbitrary code execution or denial of service against the network gateway.

Affected Products

UTT HiPER 1250GW router firmware up to and including 3.2.7-210907-180535
Web management interface handler /goform/ConfigWirelessBase_5g
Wireless 5 GHz configuration functionality processing the ssid parameter

Discovery Timeline

2026-07-05 - CVE-2026-14721 published to NVD
2026-07-06 - Last updated in NVD database

Technical Details for CVE-2026-14721

Vulnerability Analysis

The vulnerability exists in the wireless 5 GHz base configuration handler exposed through the router's web administration interface. When a request is submitted to /goform/ConfigWirelessBase_5g, the backend routine copies the attacker-supplied ssid argument into a fixed-size stack buffer without validating the input length. Supplying an oversized SSID string overwrites adjacent stack memory, including saved registers and the return address.

Because the HiPER 1250GW is a small office and branch office router, successful exploitation can compromise the device that mediates all internal network traffic. An attacker who alters control flow may pivot to intercepting, redirecting, or dropping traffic across the LAN. The vulnerability has an EPSS probability of 0.447%.

Root Cause

The root cause is missing bounds checking on the ssid request parameter before it is written into a stack-allocated buffer inside the CGI handler at /goform/ConfigWirelessBase_5g. The firmware trusts the length of a user-controlled string, which permits a classic stack smashing condition consistent with [CWE-119].

Attack Vector

Exploitation requires network reachability to the router's web management interface and valid low-privilege credentials to reach the vulnerable form handler. Once authenticated, an attacker submits a POST request to /goform/ConfigWirelessBase_5g with an SSID field containing a payload longer than the destination buffer. The overflow overwrites the saved return address on the stack. On embedded MIPS or ARM firmware without stack canaries or ASLR, this typically enables arbitrary code execution or immediate service disruption.

No verified public exploit code is documented in the referenced advisories. See the VulDB entry for CVE-2026-14721 and the associated project repository for additional technical detail.

Detection Methods for CVE-2026-14721

Indicators of Compromise

HTTP POST requests to /goform/ConfigWirelessBase_5g containing abnormally long ssid values, especially payloads exceeding 64 or 128 bytes.
Unexpected reboots, watchdog resets, or httpd process crashes on the UTT HiPER 1250GW device.
New administrative sessions or configuration changes originating from unfamiliar source IP addresses on the management interface.

Detection Strategies

Inspect web access logs on the router for requests targeting ConfigWirelessBase_5g with oversized query or body parameters.
Deploy network intrusion detection signatures that match SSID parameter lengths greater than the maximum valid IEEE 802.11 SSID of 32 bytes.
Correlate authentication events against management-interface source addresses to identify unauthorized logins preceding malformed requests.

Monitoring Recommendations

Forward router syslog and web administration logs to a centralized logging or SIEM platform for retention and correlation.
Alert on repeated connection resets or HTTP 5xx errors from the router's management interface, which may indicate exploitation attempts.
Monitor DNS, DHCP, and default gateway behavior on downstream clients for signs of traffic redirection following router compromise.

How to Mitigate CVE-2026-14721

Immediate Actions Required

Restrict access to the router's web administration interface to trusted management networks or VPN-only reachability.
Disable remote WAN-side management if it is currently enabled on the HiPER 1250GW.
Rotate administrative credentials and enforce strong, unique passwords to reduce the risk of the required low-privilege access being obtained.
Audit configured SSID values and wireless configuration entries for signs of tampering.

Patch Information

At the time of publication, no vendor security advisory or fixed firmware release is referenced in the available data. Administrators should monitor the UTT vendor portal and the VulDB vulnerability record for updates. If UTT has not published a corrected firmware version, treat affected devices as unpatched and apply compensating controls.

Workarounds

Place the router's management interface behind a firewall access control list limiting HTTP and HTTPS access to specific administrator workstations.
Segment the management VLAN from user and guest networks to reduce the population of hosts capable of reaching the vulnerable endpoint.
Where operationally feasible, replace end-of-support UTT HiPER 1250GW devices with a currently supported gateway platform until a vendor patch is released.

bash

# Example ACL restricting router management access to a trusted subnet
# Applied on an upstream firewall or L3 switch
access-list 110 permit tcp 10.10.20.0 0.0.0.255 host 192.0.2.1 eq 80
access-list 110 permit tcp 10.10.20.0 0.0.0.255 host 192.0.2.1 eq 443
access-list 110 deny   tcp any host 192.0.2.1 eq 80
access-list 110 deny   tcp any host 192.0.2.1 eq 443
access-list 110 permit ip any any