CVE-2025-9023 Overview
CVE-2025-9023 is a buffer overflow vulnerability in Tenda AC7 and AC18 wireless routers running firmware versions 15.03.06.44 and 15.03.05.19. The flaw resides in the formSetSchedLed function handling requests to the /goform/SetLEDCfg endpoint. Attackers can manipulate the Time argument to overflow a fixed-size buffer in the router's web management interface. The exploit has been publicly disclosed, increasing the risk of opportunistic attacks against exposed devices. The vulnerability is classified under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer).
Critical Impact
Remote attackers with low-privilege access can trigger memory corruption in the router's web service, leading to denial of service or potential arbitrary code execution on the device.
Affected Products
- Tenda AC7 firmware version 15.03.06.44
- Tenda AC18 firmware version 15.03.05.19
- Tenda AC7 and AC18 hardware platforms
Discovery Timeline
- 2025-08-15 - CVE-2025-9023 published to NVD
- 2025-10-03 - Last updated in NVD database
Technical Details for CVE-2025-9023
Vulnerability Analysis
The vulnerability exists in the formSetSchedLed function, which processes scheduled LED configuration requests submitted to the /goform/SetLEDCfg endpoint. The function reads the Time parameter from the HTTP request body and copies it into a fixed-size stack or heap buffer without validating the input length. Sending an oversized Time value overruns the destination buffer and corrupts adjacent memory.
Because Tenda AC7 and AC18 routers run a lightweight embedded Linux stack with limited exploit mitigations, memory corruption can lead to denial of service or arbitrary code execution under the privileges of the web management daemon. The attack is network-reachable and requires only low-privilege access to the management interface.
Root Cause
The root cause is missing bounds checking on the Time argument before it is copied into an internal buffer in formSetSchedLed. The function trusts attacker-controlled input length, violating safe memory handling practices common to embedded goform handlers in Tenda firmware.
Attack Vector
An authenticated attacker on the same network as the router, or a remote attacker if the management interface is exposed to the internet, sends a crafted HTTP POST request to /goform/SetLEDCfg containing an oversized Time parameter. The malformed request triggers the overflow during the parameter parsing routine. Refer to the GitHub CVE Report AC18 and GitHub CVE Report AC7 for technical reproduction details.
No verified proof-of-concept code is reproduced here. See the linked reports for exploitation specifics.
Detection Methods for CVE-2025-9023
Indicators of Compromise
- HTTP POST requests to /goform/SetLEDCfg containing abnormally long Time parameter values
- Unexpected reboots, web interface crashes, or httpd process restarts on Tenda AC7 or AC18 routers
- Unauthorized configuration changes to LED scheduling or other router settings following suspicious requests
Detection Strategies
- Inspect web traffic destined for the router management interface and alert on requests to /goform/SetLEDCfg with Time values exceeding expected length
- Correlate router crash logs and syslog entries with inbound HTTP requests to identify exploitation attempts
- Deploy intrusion detection signatures targeting buffer overflow patterns in goform endpoint parameters
Monitoring Recommendations
- Forward router syslog and HTTP access logs to a centralized logging or SIEM platform for anomaly analysis
- Monitor for new outbound connections from the router to unfamiliar IP addresses, which may indicate post-exploitation activity
- Audit administrative access to the router web interface and flag logins from unexpected source addresses
How to Mitigate CVE-2025-9023
Immediate Actions Required
- Disable remote WAN-side management of the router web interface until a vendor patch is available
- Restrict access to /goform/SetLEDCfg to trusted management hosts using firewall or ACL rules
- Rotate router administrator credentials and enforce strong, unique passwords
- Segment vulnerable Tenda AC7 and AC18 devices from sensitive network zones
Patch Information
No vendor advisory or firmware patch has been published at the time of writing. Monitor the Tenda Official Website for updated firmware releases addressing CVE-2025-9023. Apply firmware updates immediately once available.
Workarounds
- Disable the LED scheduling feature in the router configuration where possible
- Place affected routers behind an upstream firewall that filters unauthorized HTTP traffic to the management interface
- Replace end-of-support Tenda AC7 and AC18 devices with currently supported hardware if no patch is forthcoming
# Example: restrict access to router management interface using iptables on an upstream gateway
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -s <trusted_mgmt_subnet> -j ACCEPT
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
