CVE-2026-75004

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Improper Rule Name Quoting in Roundcube Webmail

Publication date: 2026-08-17

Last updated on: 2026-09-08

Assigner: MITRE

Description

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, improper rule name quoting could lead to managesieve_disabled_actions setting bypass via a crafted rule name in a Sieve script. This issue only affects Roundcube instances using the managesieve plugin.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-17

Last Modified

2026-09-08

Generated

2026-09-28

AI Q&A

2026-08-17

EPSS Evaluated

2026-09-26

NVD

CVE-2026-75004

EUVD

EUVD-2026-60170

Affected Vendors & Products

Vendor	Product	Version / Range
roundcube	webmail	From 1.6.0 (inc) to 1.6.18 (exc)
roundcube	webmail	From 1.7.0 (inc) to 1.7.3 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-77	The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

Attack-Flow Graph

Executive Summary

This vulnerability in Roundcube Webmail before versions 1.6.18 and 1.7.3 involves improper rule name quoting in the managesieve plugin. An attacker could bypass the managesieve_disabled_actions setting by injecting a crafted rule name in a Sieve script, potentially allowing unauthorized actions.

Detection Guidance

Check Roundcube version with: grep -r 'define.*VERSION' /var/www/roundcube/program/include/iniset.php. If using managesieve plugin, inspect Sieve scripts for crafted rule names that bypass managesieve_disabled_actions settings.

Impact Analysis

If exploited, this vulnerability could allow an authenticated attacker with access to the managesieve plugin to bypass security restrictions and perform unauthorized actions on the mail server. This could lead to data manipulation or other malicious activities depending on the server configuration.

Compliance Impact

This vulnerability could potentially lead to unauthorized access or data manipulation, which may violate compliance requirements under GDPR, HIPAA, or other regulations. Organizations using affected Roundcube versions may face compliance risks if the vulnerability is exploited to access or alter sensitive data.

Mitigation Strategies

Upgrade Roundcube to version 1.6.18 or 1.7.3 immediately. Disable the managesieve plugin if not required. Review Sieve scripts for suspicious rule names and restrict plugin access.

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