CVE-2026-18898 Overview
CVE-2026-18898 is a stack-based buffer overflow in the UTT HiPER 1200GW router through firmware version v2.5.3-170306. The vulnerability resides in the strcpy call within the /goform/ConfigAdvideo endpoint. An attacker can trigger the overflow by manipulating the timestart argument, corrupting adjacent stack memory. The flaw is exploitable remotely and requires only low-privilege access. Public exploit details have been released, increasing the risk of opportunistic attacks. The vendor was notified but did not respond to the disclosure.
Critical Impact
Remote attackers can corrupt stack memory in the router's web management interface, potentially leading to arbitrary code execution or device compromise.
Affected Products
- UTT HiPER 1200GW router
- Firmware versions up to and including v2.5.3-170306
- Devices exposing the /goform/ConfigAdvideo web management endpoint
Discovery Timeline
- 2026-08-05 - CVE CVE-2026-18898 published to NVD
- 2026-08-05 - Last updated in NVD database
Technical Details for CVE-2026-18898
Vulnerability Analysis
The vulnerability is a classic stack-based buffer overflow classified under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer). The HTTP handler at /goform/ConfigAdvideo accepts a timestart parameter and passes it directly to strcpy without bounds checking. Because strcpy copies until a null terminator, an oversized timestart value overflows the fixed-size destination buffer on the stack. This overwrites saved registers, return addresses, and adjacent local variables. Successful exploitation can hijack control flow of the web management daemon running on the device. Given typical embedded router builds lack modern mitigations such as stack canaries or full ASLR, reliable code execution is plausible.
Root Cause
The root cause is unsafe use of strcpy on attacker-controlled input inside the ConfigAdvideo form handler. The code assumes the incoming timestart value fits within the destination buffer instead of validating its length before copying.
Attack Vector
Exploitation is network-based against the router's web administration interface. An authenticated user with low privileges can submit a crafted HTTP request to /goform/ConfigAdvideo containing an oversized timestart parameter. No user interaction is required. Where the management interface is exposed to untrusted networks or the internet, the exposure surface is substantially broader.
No verified proof-of-concept code is reproduced here. Technical details are available in the GitHub PoC Repository and the VulDB CVE Details.
Detection Methods for CVE-2026-18898
Indicators of Compromise
- HTTP POST requests to /goform/ConfigAdvideo containing unusually long timestart values
- Router web daemon crashes, restarts, or watchdog reboots correlated with inbound management traffic
- Unexpected outbound connections initiated by the router following administrative HTTP activity
- Configuration or firmware changes with no corresponding administrative action
Detection Strategies
- Inspect web-server and router syslog output for repeated ConfigAdvideo requests with abnormal parameter lengths
- Deploy network IDS/IPS signatures that flag HTTP requests to /goform/ConfigAdvideo where timestart exceeds a conservative byte threshold
- Baseline expected administrative traffic to the router and alert on deviations in source IP, frequency, or payload size
Monitoring Recommendations
- Forward router logs to a centralized logging platform for correlation and retention
- Monitor for management-interface reachability from untrusted networks or the public internet
- Track device availability metrics; repeated crashes of the HTTP daemon can indicate exploitation attempts
How to Mitigate CVE-2026-18898
Immediate Actions Required
- Restrict access to the router's web management interface to trusted management VLANs or specific administrator IP addresses
- Disable remote WAN-side administration if enabled
- Rotate administrative credentials, since exploitation requires low-privilege authenticated access
- Segment vulnerable devices from sensitive internal networks until a fix is available
Patch Information
No vendor patch is available. UTT did not respond to the disclosure. Organizations should treat affected HiPER 1200GW devices as unpatched and plan replacement or compensating controls. Consult the VulDB Vulnerability Detail for updates on vendor response.
Workarounds
- Block external access to TCP ports serving the router's web administration interface at the perimeter firewall
- Place the device behind a reverse proxy or VPN that enforces authentication before exposing management endpoints
- Replace end-of-support or unmaintained UTT HiPER 1200GW units with actively supported hardware where feasible
- Apply web application firewall rules that drop HTTP requests to /goform/ConfigAdvideo with oversized parameter values
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
