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Fencer Vulns
medium 5.4

CVE-2021-26925 json

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

published 2021-02-09 5 y ago modified 2026-06-17 4 mo ago also BIT-roundcube-2021-26925 , EUVD-2021-13707

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits
0
none known

Summary

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

Patch / fix

  • bitnami roundcube 1.4.11
  • roundcube webmail 1.4.11
  • roundcube Debian 14, Debian 13, Debian 12 1.4.11+dfsg.1-1

debian advisories DEBIAN-CVE-2021-26925

  • roundcube Ubuntu 22.04 LTS 1.5.0+dfsg.1-2

ubuntu advisories UBUNTU-CVE-2021-26925

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • roundcubemail Arch Linux 1.4.11-1

arch linux advisories AVG-1551

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-26925 updated

roundcube: Cross-site scripting via crafted Cascading Style Sheets

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.02% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N
OSV 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
bitnami roundcube
<1.4.11
1.4.11

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.