PT-2026-29983 · Unknown+1 · Roundcube Webmail+1

Nullcathedral1 · Published 2026-03-18 · Updated 2026-05-07 · CVE-2026-35544

Positive Technologies (AI Summary)

CVSS v3.1

5.3

Medium

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Name of the Vulnerable Software and Affected Versions Roundcube Webmail versions prior to 1.5.14 and prior to 1.6.14

Description A flaw exists in Roundcube Webmail that stems from inadequate sanitization of Cascading Style Sheets (CSS) within HTML email messages. This can allow for a bypass of existing mitigations through the use of the '!important' declaration in CSS.

Recommendations Update Roundcube Webmail to version 1.5.14 or later. Update Roundcube Webmail to version 1.6.14 or later.

Fix

Weakness Enumeration

CWE-669

Related Identifiers

BDU:2026-06326

CVE-2026-35544

GHSA-XPQH-GRPW-4XMG

Affected Products

Red Os

Roundcube Webmail

References · 21

• https://github.com/roundcube/roundcubemail/commit/226811a1c974271dbedca72672923abaff8191c0 · Patch
• https://github.com/roundcube/roundcubemail/commit/099009b9c8e1d3c636fb9a5af72f7c2596018662 · Patch
• https://github.com/roundcube/roundcubemail/commit/57dec0c127b98e0c8e3b9c26c80049b9c4bcaea7 · Patch
• https://osv.dev/vulnerability/GHSA-xpqh-grpw-4xmg · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-35544 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-35544 · Vendor Advisory
• https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-35544 · Security Note
• https://bdu.fstec.ru/vul/2026-06326 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2026-35544 · Vendor Advisory
• https://ubuntu.com/security/CVE-2026-35544 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-35544 · Security Note
• https://github.com/roundcube/roundcubemail/releases/tag/1.5.14 · Note
• https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5 · Note
• https://github.com/roundcube/roundcubemail/releases/tag/1.6.14 · Note