PT-2026-29978 · Roundcube+1 · Roundcube Webmail+1

Y0Us · CVE-2026-35539 · Published 2026-03-18 · Updated 2026-05-07

Positive Technologies (AI Summary)

CVSS v2.0

6.4

Medium

Base vector

AV:N/AC:L/Au:N/C:P/I:P/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 allows for cross-site scripting (XSS). This occurs due to inadequate sanitization of HTML attachments when previewed. An attacker can exploit this by having a victim preview a specially crafted text/html attachment.

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

Exploit

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

BDU:2026-06179

CVE-2026-35539

GHSA-X4Q5-8J5G-HPJC

Affected Products

Red Os

Roundcube Webmail

References · 22

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/35xxx/CVE-2026-35539.json · Exploit
• https://github.com/roundcube/roundcubemail/commit/d742954ccbcdee7020f8f2e7c49ce0fca5a0efab · Patch
• https://github.com/roundcube/roundcubemail/commit/1b30edf5369668c92fe91dae3d52e477c808aa4f · Patch
• https://github.com/roundcube/roundcubemail/commit/10a6d1fa8acac85c727b0a6ae4a6642bfa27bea1 · Patch
• 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-2026-35539 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-35539 · Security Note
• https://osv.dev/vulnerability/GHSA-x4q5-8j5g-hpjc · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-35539 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2026-35539 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-35539 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2026-35539 · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-06179 · Security Note
• https://ubuntu.com/security/CVE-2026-35539 · Vendor Advisory
• https://github.com/roundcube/roundcubemail/releases/tag/1.6.14 · Note