CVE-2024-25753 Overview
CVE-2024-25753 is a stack-based buffer overflow [CWE-121] in the Tenda AC9 v3.0 wireless router running firmware version v.15.03.06.42_multi. The flaw resides in the formSetDeviceName function of the router's web management interface. An adjacent-network attacker can send a crafted request to trigger the overflow and execute arbitrary code on the device. Successful exploitation grants control over the router, exposing all traffic and connected clients to interception, redirection, or further attack.
Critical Impact
Remote code execution on Tenda AC9 routers over the local network, leading to full device compromise, persistence in home and small-office networks, and lateral movement into connected systems.
Affected Products
- Tenda AC9 v3.0 hardware
- Tenda AC9 firmware v.15.03.06.42_multi
- CPE: cpe:2.3:o:tenda:ac9_firmware:5.03.06.42_multi:*:*:*:*:*:*:*
Discovery Timeline
- 2024-02-22 - CVE-2024-25753 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-25753
Vulnerability Analysis
The formSetDeviceName handler processes device-naming requests submitted through the Tenda AC9 web interface. The function copies attacker-controlled input into a fixed-size stack buffer without validating the length of the supplied value. When the input exceeds the buffer's capacity, adjacent stack memory, including the saved return address, is overwritten.
Because the router firmware runs on a MIPS-based Linux platform with limited exploit mitigations, controlling the return address commonly leads to arbitrary code execution as the web server process. The web daemon typically runs with elevated privileges, so a successful overflow grants full control of the device. The attacker can then modify DNS settings, install persistent implants, or pivot into the internal network.
Root Cause
The root cause is missing bounds checking in the formSetDeviceName function. User-supplied device-name data is passed to an unsafe string copy operation into a stack buffer of fixed length. This is a classic instance of [CWE-121: Stack-based Buffer Overflow] arising from unsanitized web-form input reaching a low-level string routine.
Attack Vector
Exploitation requires network adjacency, typically an attacker on the same Wi-Fi network or wired LAN segment as the router. No authentication or user interaction is required. The attacker sends an HTTP POST request to the vulnerable endpoint with an oversized deviceName parameter, corrupting the stack and hijacking execution flow.
See the public proof-of-concept documenting the formSetDeviceName crash for the request structure and offsets used to reach the vulnerable code path.
Detection Methods for CVE-2024-25753
Indicators of Compromise
- Oversized deviceName values in HTTP POST requests to the router's management interface, particularly requests exceeding a few hundred bytes for this parameter.
- Unexpected reboots or crashes of the httpd process on the Tenda AC9, often the signature of a failed overflow attempt.
- DNS or routing configuration changes that do not correspond to administrator activity.
- Outbound connections from the router itself to unfamiliar IP addresses, indicative of implanted code.
Detection Strategies
- Inspect network captures on the LAN for HTTP requests targeting /goform/setDeviceName or similar management endpoints with abnormally long parameters.
- Deploy an IDS or IPS rule that alerts on oversized form fields directed at Tenda AC9 management IPs.
- Baseline management-interface traffic and flag any administrative changes originating from non-administrator hosts.
Monitoring Recommendations
- Enable syslog forwarding from the router to a central log collector, if supported, and monitor for repeated httpd restarts.
- Track DHCP and DNS configuration deltas on the router, since altered DNS is a common post-exploitation step.
- Monitor client devices for signs of traffic redirection, such as invalid TLS certificate warnings on trusted sites.
How to Mitigate CVE-2024-25753
Immediate Actions Required
- Restrict access to the router's web management interface to a dedicated administrative host or VLAN, and disable remote management on the WAN interface.
- Change default administrator credentials and use a strong passphrase, even though this flaw does not require authentication, to limit other attack paths.
- Isolate untrusted devices, including guest and IoT endpoints, on a separate SSID or VLAN so adjacent-network exploitation is not possible from those segments.
- Replace the Tenda AC9 v3.0 with a supported device if the vendor has not released a firmware update addressing this issue.
Patch Information
No vendor advisory or fixed firmware version is referenced in the NVD entry for CVE-2024-25753. Administrators should consult the Tenda support portal for the latest firmware for the AC9 v3.0 and apply any release newer than v.15.03.06.42_multi that documents a fix for formSetDeviceName. Until a patch is confirmed, treat the device as vulnerable.
Workarounds
- Block LAN client access to the router's management port (typically TCP/80 or TCP/443) except from a specified administrator address using ACLs where the device supports them.
- Disable UPnP and any cloud-management or remote-access features on the router to reduce the exposed attack surface.
- Place the router behind an additional firewall or place vulnerable segments behind a trusted gateway that can inspect and drop malformed management traffic.
# Example: restrict management access on an upstream firewall (iptables)
# Allow only 192.0.2.10 to reach the router's web UI at 192.168.0.1
iptables -A FORWARD -s 192.0.2.10 -d 192.168.0.1 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -d 192.168.0.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.0.1 -p tcp --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
