What is CVE-2020-11734?

CVE-2020-11734 is a medium-severity vulnerability in Cybersolutions Cybermail, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2020-04-13.

How severe is CVE-2020-11734?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Cybersolutions Cybermail

CVE-2020-11734

cgi-bin/go in CyberSolutions CyberMail 5 or later allows XSS via the ACTION parameter.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2020-04-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.010 (60.2th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 60th percentile — 60.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Cybersolutions Cybermail — versions 5.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

gist.github.com/tonykuo76/d2480727faeb768a97800db3058dceed (Exploit, Third Party Advisory)
www.cybersolutions.co.jp/product/cybermail/ (Vendor Advisory)
www.chtsecurity.com/news/6b907733-c475-4504-b3b7-793442d34335 (Third Party Advisory)

Frequently asked questions

What is CVE-2020-11734?: CVE-2020-11734 is a medium-severity vulnerability in Cybersolutions Cybermail, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2020-04-13.
How severe is CVE-2020-11734?: Medium severity. CVSS v3 base score is 6.1 out of 10.