What is CVE-2021-31739?

CVE-2021-31739 is a medium-severity vulnerability in Seppmail, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2022-11-18.

How severe is CVE-2021-31739?

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

XSS in Seppmail

CVE-2021-31739

The SEPPmail solution is vulnerable to a Cross-Site Scripting vulnerability (XSS), because user input is not correctly encoded in HTML attributes when returned by the server.SEPPmail 11.1.10 allows XSS via a recipient address.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2022-11-18 · 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: 0.004 (36.1th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 36.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000

Affected products

Seppmail — versions 11.1.10

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

www.pentagrid.ch/en/blog/multiple-vulnerabilities-in-seppmail/ (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-31739?: CVE-2021-31739 is a medium-severity vulnerability in Seppmail, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2022-11-18.
How severe is CVE-2021-31739?: Medium severity. CVSS v3 base score is 6.1 out of 10.