What is CVE-2019-3940?

CVE-2019-3940 is a critical-severity vulnerability in Advantech Webaccess, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 9.8/10. Published 2019-04-09.

How severe is CVE-2019-3940?

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

Arbitrary file upload in Advantech Webaccess

CVE-2019-3940

Advantech WebAccess 8.3.4 is vulnerable to file upload attacks via unauthenticated RPC call. An unauthenticated, remote attacker can use this vulnerability to execute arbitrary code.

Vulnerability class: Unrestricted File Upload

Published 2019-04-09 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.041 (90.7th percentile), scored 2026-10-23.

Low probability of exploitation in the next 30 days, but still tracked. 91st percentile — 90.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.041 · newest: 0.041 · change: 0.000

Affected products

Advantech Webaccess — versions 8.3.4

Weakness classification (CWE)

CWE-434 — Unrestricted Upload of File with Dangerous Type

References

www.tenable.com/security/research/tra-2019-15 (Third Party Advisory)
www.securityfocus.com/bid/107847 (VDB Entry, Third Party Advisory, vdb-entry)

Frequently asked questions

What is CVE-2019-3940?: CVE-2019-3940 is a critical-severity vulnerability in Advantech Webaccess, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 9.8/10. Published 2019-04-09.
How severe is CVE-2019-3940?: Critical severity. CVSS v3 base score is 9.8 out of 10.