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VulnerabilityPublished

CVE-2026-3972: Tenda W3 · Stack-based Buffer Overflow

Affects Tenda W3Source CVE Database V5

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Public exploit available · CVSS 8.7 High.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 12 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    CVSS exploit maturity: proof of concept public

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
TendaW3Affected
  • =1.0.0.3(2204)
Fixed in–

AI-suggested

To mitigate CVE-2026-3972, organizations should first verify if they are using the affected Tenda W3 firmware version 1.0.0.3(2204). 2) Disable remote management features and unnecessary services on the router to reduce the attack surface. 3) Monitor network traffic for unusual activity or attempts to access the /goform/setcfm endpoint. 4) Employ network intrusion detection/prevention systems (IDS/IPS) with signatures for known exploit attempts targeting this vulnerability. 5) Replace or upgrade affected devices to models with patched firmware as soon as updates become available from the vendor. 6) Educate users and administrators about the risk of local network threats and enforce strong internal network security policies. 7) Regularly audit device firmware versions and configurations to ensure timely detection of vulnerable devices. These measures help reduce the risk of exploitation until a vendor patch is released.

Description

CVE-2026-3972 is a high-severity stack-based buffer overflow vulnerability in the Tenda W3 router firmware version 1.0.0.3(2204). The flaw exists in the HTTP handler component, specifically in the formSetCfm function processing the funcpara1 argument. Exploitation requires local network access and does not need authentication or user interaction. Successful exploitation can lead to full compromise of the device due to control over code execution on the stack. Although no public exploits are currently observed in the wild, proof-of-concept code has been published, increasing risk. The vulnerability affects the confidentiality, integrity, and availability of the affected device. Organizations using Tenda W3 routers should prioritize patching or mitigating this issue to prevent potential lateral movement or network compromise.

References

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