CVE-2021-31624
HighCVSS 8.8Exploitation Probability (EPSS)
Elevated risk62th percentile - higher than 62% of all known CVEs
Summary
A buffer overflow vulnerability was found in Tenda AC9 routers versions V1.0 through V15.03.05.19(6318) and AC9 V3.0 V15.03.06.42_multi. Attackers can exploit the 'urls' parameter to execute arbitrary code on the device.
Risk Assessment
The risk involves potential remote code execution by an unauthenticated attacker, which could lead to full device compromise, network traffic interception, or further attacks on local network devices.
Recommendation
Immediately update the Tenda AC9 router firmware to the latest available version that fixes this vulnerability. If no update is available, restrict management interface access to trusted networks only.
Other vulnerabilities in Tenda AC9
See all- CVE-2026-104611Critical
A vulnerability was detected in Tenda AC9 15.03.02.13. Affected is an unknown function of the file /goform/fast_setting_internet_set of the component POST Request Handler. Performing a manipulation of the argument netWanType results in stack-based buffer overflow. The attack is possible to be carried out remotely. The exploit is now public and may be used.
- CVE-2026-86300High
A flaw has been found in Tenda AC9 15.03.05.14. This impacts the function R7WebsSecurityHandler of the component Web Management. This manipulation causes improper authentication. The attack may be initiated remotely. The exploit has been published and may be used.
- CVE-2025-14286Medium
A vulnerability was determined in Tenda AC9 15.03.05.14_multi. Affected by this vulnerability is an unknown functionality of the file /cgi-bin/DownloadCfg.jpg of the Configuration File Handler component. This manipulation causes information disclosure. The attack may be initiated remotely. The exploit has been publicly disclosed and may be utilized.
- CVE-2022-36233Medium
A buffer overflow vulnerability was discovered in the Tenda AC9 router firmware version V15.03.2.13 in the httpd process. The issue occurs in the form_fast_setting_wifi_set function, potentially allowing remote code execution.
- CVE-2021-31627High
A buffer overflow vulnerability was found in Tenda AC9 routers versions V1.0 through V15.03.05.19(6318) and AC9 V3.0 V15.03.06.42_multi. Attackers can exploit the 'index' parameter to execute arbitrary code.
Original NVD description (English source)
Buffer Overflow vulnerability in Tenda AC9 V1.0 through V15.03.05.19(6318), and AC9 V3.0 V15.03.06.42_multi, allows attackers to execute arbitrary code via the urls parameter.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

