Cyber Resilience

CVE-2023-40891

CriticalPublic PoC

Published: 24 August 2023

Published
24 August 2023
Modified
08 December 2025
KEV Added
—
Patch
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CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0015 35.5th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2023-40891 is a critical-severity Out-of-bounds Write (CWE-787) vulnerability in Tenda Ac8 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, ranked at the 35.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

Tenda AC8 v4 US_AC8V4.0si_V16.03.34.06_cn was discovered to contain a stack overflow via parameter firewallEn at /goform/SetFirewallCfg.

CWE(s)
CWE-787

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

tenda
ac8 firmware
16.03.34.06

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SI-16 Memory Protection
addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

References