CVE-2026-35544
Roundcube Webmail CSS Injection Vulnerability
Description
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important.
INFO
Published Date :
April 3, 2026, 5:16 a.m.
Last Modified :
April 9, 2026, 1:09 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-35544
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 8254265b-2729-46b6-b9e3-3dfca2d5bfca | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Roundcube Webmail to 1.5.14 or 1.6.14.
- Apply vendor patches for earlier versions.
Public PoC/Exploit Available at Github
CVE-2026-35544 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-35544.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-35544 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-35544
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
DSA and DLA for Debian last 14 days
Python
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-35544 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-35544 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Apr. 09, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:* versions up to (including) 1.5.13 *cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:* versions from (including) 1.6.0 up to (including) 1.6.13 Added Reference Type MITRE: https://github.com/roundcube/roundcubemail/commit/099009b9c8e1d3c636fb9a5af72f7c2596018662 Types: Patch Added Reference Type MITRE: https://github.com/roundcube/roundcubemail/commit/226811a1c974271dbedca72672923abaff8191c0 Types: Patch Added Reference Type MITRE: https://github.com/roundcube/roundcubemail/commit/57dec0c127b98e0c8e3b9c26c80049b9c4bcaea7 Types: Patch Added Reference Type MITRE: https://github.com/roundcube/roundcubemail/releases/tag/1.5.14 Types: Release Notes Added Reference Type MITRE: https://github.com/roundcube/roundcubemail/releases/tag/1.6.14 Types: Release Notes Added Reference Type MITRE: https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5 Types: Release Notes Added Reference Type MITRE: https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14 Types: Vendor Advisory -
New CVE Received by [email protected]
Apr. 03, 2026
Action Type Old Value New Value Added Description An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Added CWE CWE-669 Added Reference https://github.com/roundcube/roundcubemail/commit/099009b9c8e1d3c636fb9a5af72f7c2596018662 Added Reference https://github.com/roundcube/roundcubemail/commit/226811a1c974271dbedca72672923abaff8191c0 Added Reference https://github.com/roundcube/roundcubemail/commit/57dec0c127b98e0c8e3b9c26c80049b9c4bcaea7 Added Reference https://github.com/roundcube/roundcubemail/releases/tag/1.5.14 Added Reference https://github.com/roundcube/roundcubemail/releases/tag/1.6.14 Added Reference https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5 Added Reference https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14