CVE-2023-40891
CWE-787Published: August 24, 2023· Updated: Jun 17, 2026
Official Description
Tenda AC8 v4 US_AC8V4.0si_V16.03.34.06_cn was discovered to contain a stack overflow via parameter firewallEn at /goform/SetFirewallCfg.
Risk Analysis
A stack overflow vulnerability in the Tenda AC8 firmware can be triggered via the firewallEn parameter. This critical flaw is rated 9.8 and allows unauthenticated remote attackers to gain control of the device.
No public exploit is known for this vulnerability, and it is not in the CISA KEV. The vulnerability is remotely exploitable.
Update the Tenda AC8 firmware to the latest version. Restrict access to the web management interface to trusted networks.
Technical Analysis
CVE-2023-40891 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.
From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (2)
Quick Facts
Related CVEs (CWE-787)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2023-40891 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts