What is CVE-2022-40855?

CVE-2022-40855 is a critical-severity vulnerability in Tenda W20e, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2022-09-23.

How severe is CVE-2022-40855?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Tenda W20e

CVE-2022-40855

Tenda W20E router V15.11.0.6 contains a stack overflow in the function formSetPortMapping with post request 'goform/setPortMapping/'. This vulnerability allows attackers to cause a Denial of Service (DoS) or Remote Code Execution (RCE) via the portMappingServer, portMappingProtocol, portMappingWan, porMappingtInternal, and portMappingExternal parameters.

Vulnerability class: Buffer Overflow

Published 2022-09-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.141 (96.6th percentile), scored 2026-10-25.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 96.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.138 · newest: 0.141 · change: +0.003

Affected products

Tenda W20e
Tenda W20e Firmware — versions 15.11.0.6

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

github.com/CPSeek/Router-vuls/blob/main/Tenda/W20E/formSetPortMapping.md (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2022-40855?: CVE-2022-40855 is a critical-severity vulnerability in Tenda W20e, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2022-09-23.
How severe is CVE-2022-40855?: Critical severity. CVSS v3 base score is 9.8 out of 10.