What is CVE-2026-74998?

CVE-2026-74998 is a high-severity vulnerability in Roundcube Webmail, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-08-17.

How severe is CVE-2026-74998?

High severity. CVSS v3 base score is 7.2 out of 10.

XSS in Roundcube Webmail

CVE-2026-74998

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascading Style Sheets) proxy were not validated, which may result in information disclosure or XSS (cross-site scripting) via MIME sniffing.

Vulnerability class: XSS (Cross-Site Scripting)

CVSS v3 metric

CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.

Affected products

Roundcube Webmail — versions 1.6.0, 1.7.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

cve@mitre.org
cve@mitre.org
cve@mitre.org
cve@mitre.org
cve@mitre.org

Frequently asked questions

What is CVE-2026-74998?: CVE-2026-74998 is a high-severity vulnerability in Roundcube Webmail, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-08-17.
How severe is CVE-2026-74998?: High severity. CVSS v3 base score is 7.2 out of 10.