CVE-2025-11328 Overview
CVE-2025-11328 is a stack-based buffer overflow vulnerability in the Tenda AC18 wireless router running firmware version 15.03.05.19(6318). The flaw resides in the /goform/SetDDNSCfg endpoint, where the ddnsEn parameter is processed without proper bounds checking. An authenticated remote attacker can exploit this issue over the network to corrupt stack memory on the device. The vulnerability is tracked under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). Public technical details describing the exploit have been released, increasing the likelihood of opportunistic attacks against exposed devices.
Critical Impact
Successful exploitation can crash the router or enable arbitrary code execution in the context of the device's web management service, compromising confidentiality, integrity, and availability of the affected hardware.
Affected Products
- Tenda AC18 hardware router
- Tenda AC18 firmware version 15.03.05.19(6318)
- Deployments exposing the device web management interface to untrusted networks
Discovery Timeline
- 2025-10-06 - CVE-2025-11328 published to NVD
- 2025-10-07 - Last updated in NVD database
Technical Details for CVE-2025-11328
Vulnerability Analysis
The vulnerability exists in the HTTP request handler for /goform/SetDDNSCfg, a configuration endpoint used to manage Dynamic DNS (DDNS) settings on the Tenda AC18 router. The handler reads the ddnsEn parameter from the incoming request and copies its contents into a fixed-size stack buffer without validating the input length. Submitting an oversized value for ddnsEn overwrites adjacent stack memory, including saved return addresses and frame pointers used by the MIPS-based firmware. This class of memory corruption is well-documented across Tenda consumer router firmware and aligns with CWE-119. Public proof-of-concept documentation describing the parameter and crash conditions is available in the GitHub Vulnerability Document.
Root Cause
The root cause is missing length validation when copying user-controlled input into a fixed-size stack buffer. The firmware trusts the size of the ddnsEn query parameter and uses an unsafe string-copy routine to move data from the request into local storage. Attackers can supply a payload larger than the destination buffer to overwrite the saved return address.
Attack Vector
The attack is network-reachable and requires low-privilege credentials to authenticate to the router's web interface. Once authenticated, an attacker sends a crafted HTTP request to /goform/SetDDNSCfg containing an oversized ddnsEn parameter. No user interaction is required, and exploitation can be automated against discoverable devices.
No verified exploitation code is reproduced here. Refer to the GitHub Vulnerability Document and VulDB entry #327211 for technical proof-of-concept details.
Detection Methods for CVE-2025-11328
Indicators of Compromise
- HTTP POST or GET requests to /goform/SetDDNSCfg containing unusually long ddnsEn values
- Unexpected reboots, watchdog resets, or httpd crashes on the Tenda AC18 router
- Outbound connections from the router to unfamiliar command-and-control hosts following configuration requests
- Configuration changes to DDNS settings that were not initiated by an administrator
Detection Strategies
- Inspect web management traffic for requests targeting /goform/SetDDNSCfg with parameter values exceeding typical lengths (for example, more than 64 bytes for ddnsEn).
- Correlate router crash logs and syslog entries with inbound HTTP traffic to identify exploitation attempts.
- Monitor for repeated failed authentication followed by malformed configuration requests, which can indicate credential stuffing combined with exploit attempts.
Monitoring Recommendations
- Forward router syslog and authentication events to a centralized SIEM or data lake for anomaly analysis.
- Alert on management-interface access from outside designated administrative networks.
- Track firmware versions across the fleet and flag any AC18 device still running 15.03.05.19(6318).
How to Mitigate CVE-2025-11328
Immediate Actions Required
- Restrict access to the router's web management interface to trusted internal hosts only and disable remote (WAN-side) administration.
- Change default and reused credentials on all Tenda AC18 devices to reduce the value of the required low-privilege authentication.
- Disable the DDNS feature if it is not in active operational use to reduce the attack surface of /goform/SetDDNSCfg.
Patch Information
No vendor security advisory or patched firmware has been published at the time of NVD listing. Refer to the Tenda Official Website for firmware updates and monitor VulDB CTI #327211 for tracking changes. Where no patch is available, consider replacing end-of-life or unsupported AC18 units with a maintained device.
Workarounds
- Place affected routers behind an upstream firewall that blocks inbound HTTP/HTTPS to the management interface.
- Segment IoT and network infrastructure devices onto a dedicated VLAN with strict egress filtering.
- Apply ACLs on the router itself to limit management access to specific administrative IP addresses.
- Monitor vendor channels for an official firmware fix and schedule deployment as soon as it becomes available.
# Example: restrict management access using upstream firewall rules
# Allow management only from the trusted admin subnet
iptables -A FORWARD -p tcp -s 10.10.0.0/24 -d 192.168.0.1 --dport 80 -j ACCEPT
iptables -A FORWARD -p tcp -d 192.168.0.1 --dport 80 -j DROP
iptables -A FORWARD -p tcp -d 192.168.0.1 --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
