What is CVE-2021-26925?

CVE-2021-26925 is a medium-severity vulnerability in Roundcube Webmail, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-02-09.

How severe is CVE-2021-26925?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Roundcube Webmail

CVE-2021-26925

Roundcube before 1.4.11 allows XSS via crafted Cascading Style Sheets (CSS) token sequences during HTML email rendering.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-02-09 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.010 (61.6th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 62nd percentile — 61.6% 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

Roundcube Webmail
Fedoraproject Fedora — versions 32, 33

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

roundcube.net/news/2021/02/08/security-update-1.4.11 (Third Party Advisory, Release Notes)
github.com/roundcube/roundcubemail/commit/9dc276d5f26042db02754fa1bac6fbd683c6d… (Patch, Third Party Advisory)
lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)

Frequently asked questions

What is CVE-2021-26925?: CVE-2021-26925 is a medium-severity vulnerability in Roundcube Webmail, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-02-09.
How severe is CVE-2021-26925?: Medium severity. CVSS v3 base score is 5.4 out of 10.