XSS in Everpress Mailster

CVE-2025-64203

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in EverPress Mailster mailster allows Reflected XSS.This issue affects Mailster: from n/a through < 4.1.14.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.002 (11.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 11.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-64203: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2025-64203?
CVE-2025-64203 is a high-severity vulnerability in Everpress Mailster, classified under Cross-site Scripting. CVSS score: 7.1/10. Published 2025-12-18.
How severe is CVE-2025-64203?
High severity. CVSS v3 base score is 7.1 out of 10.