What is CVE-2021-42839?

CVE-2021-42839 is a high-severity vulnerability in Grand Vice Info Co. Webopac7, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 8.8/10. Published 2021-11-15.

How severe is CVE-2021-42839?

High severity. CVSS v3 base score is 8.8 out of 10.

Arbitrary file upload in Grand Vice Info Co. Webopac7

CVE-2021-42839

Grand Vice info Co. webopac7 file upload function fails to filter special characters. While logging in with general user’s permission, remote attackers can upload malicious script and execute arbitrary code to control the system or interrupt services.

Vulnerability class: Unrestricted File Upload

Published 2021-11-15 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.024 (83.6th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 84th percentile — 83.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.024 · newest: 0.024 · change: +0.001

Affected products

Grand Vice Info Co. Webopac7 — versions 7.1.20160701, 1.8.20160701
Vice Webopac — versions 1.8.20160701, 7.1.20160701

Weakness classification (CWE)

CWE-434 — Unrestricted Upload of File with Dangerous Type

References

www.twcert.org.tw/tw/cp-132-5288-9d546-1.html (Third Party Advisory)

Frequently asked questions

What is CVE-2021-42839?: CVE-2021-42839 is a high-severity vulnerability in Grand Vice Info Co. Webopac7, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 8.8/10. Published 2021-11-15.
How severe is CVE-2021-42839?: High severity. CVSS v3 base score is 8.8 out of 10.