CVE-2026-114722: Medium severity Roundcube Roundcube Webmail vulnerability

Q: Which Roundcube releases require remediation?

Roundcube Webmail releases before 1.6.20 are affected, as are 1.7.x releases before 1.7.5. Updating to 1.6.20 or 1.7.5 addresses the issue.

Q: What does an attacker need to exploit this issue?

The attacker needs to supply an HTML message containing CSS that uses the affected parsing cases, including an at-rule prologue such as @layer a; or selectors beginning with ::. The vulnerability is rated with no required privileges and no user interaction in the supplied CVSS vector.

Q: What is the practical impact of successful exploitation?

A crafted message can cause CSS selectors to apply outside the message body to the Roundcube interface. This can be used to restyle application chrome for UI redressing and spoofing.

Published Oct 22, 2026

Updated

Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by a CSS scoping bypass in HTML messages. rcubeutils::modcssstyles() did not treat an at-rule prologue such as @layer a; as a selector boundary, and did not handle selectors beginning with ::, so selectors following an at-rule were left unscoped and applied to the whole Roundcube interface instead of being confined to the message body. This allows an HTML message to restyle application chrome for UI redressing and spoofing. Upstream fixed this in the commit “Fix CSS scoping bypass in HTML messages using at-rules”.

Affected Software

1 affected component

Roundcube Roundcube Webmail<1.6.20, >=1.7.0<1.7.5

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade Roundcube Webmail to a version that resolves this vulnerability.
Patch Fix CSS scoping bypass in HTML messages using at-rules

Event History

Oct 22, 2026

CVE Published

via MITRE·01:39 AM

Data Sourced

via MITRE·01:39 AM

DescriptionSeverityWeakness

Frequently Asked Questions

Which Roundcube releases require remediation?

Roundcube Webmail releases before 1.6.20 are affected, as are 1.7.x releases before 1.7.5. Updating to 1.6.20 or 1.7.5 addresses the issue.

What does an attacker need to exploit this issue?

The attacker needs to supply an HTML message containing CSS that uses the affected parsing cases, including an at-rule prologue such as @layer a; or selectors beginning with ::. The vulnerability is rated with no required privileges and no user interaction in the supplied CVSS vector.

What is the practical impact of successful exploitation?

A crafted message can cause CSS selectors to apply outside the message body to the Roundcube interface. This can be used to restyle application chrome for UI redressing and spoofing.

CVE-2026-114722: Medium severity Roundcube Roundcube Webmail vulnerability

Affected Software

Remediation

Event History

Frequently Asked Questions

Which Roundcube releases require remediation?

What does an attacker need to exploit this issue?

What is the practical impact of successful exploitation?

Company

Resources

Contact

Frequently Asked Questions

Which Roundcube releases require remediation?

What does an attacker need to exploit this issue?

What is the practical impact of successful exploitation?