---
title: "CVE-2026-35544\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2026-35544?format=md
keywords: index, follow
---

# CVE-2026-35544

Publication date 3 April 2026

Last updated 8 April 2026

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**5.3 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2026-35544?format=md#impact-score)

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## 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.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| roundcube | 26.04 LTS resolute | Needs evaluation |
| 25.10 questing | Ignored end of life, was needs-triage |
| 24.04 LTS noble | Needs evaluation |
| 22.04 LTS jammy | Needs evaluation |
| 20.04 LTS focal | Needs evaluation |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | Needs evaluation |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

5.3 · Medium

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | Low |
  | Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 5.3 · Medium |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-35544)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-35544)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-35544)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-35544)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-35544>
* <https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14>
* <https://nullcathedral.com/posts/2026-03-18-roundcube-round-two-three-more-sanitizer-bypasses/#css-position-fixed-important>
* <https://github.com/roundcube/roundcubemail/commit/099009b9c8e1d3c636fb9a5af72f7c2596018662>
* <https://github.com/roundcube/roundcubemail/commit/226811a1c974271dbedca72672923abaff8191c0>
* <https://github.com/roundcube/roundcubemail/commit/57dec0c127b98e0c8e3b9c26c80049b9c4bcaea7>
* <https://github.com/roundcube/roundcubemail/releases/tag/1.5.14>
* <https://github.com/roundcube/roundcubemail/releases/tag/1.6.14>
* <https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5>