Roundcube Webmail up to 1.6.20/1.7.5 _uid command injection

Summaryinfo

A vulnerability has been found in Roundcube Webmail up to 1.6.20/1.7.5 and classified as critical. This impacts an unknown function. Performing a manipulation of the argument _uid results in command injection. This vulnerability is known as CVE-2026-126813. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in Roundcube Webmail up to 1.6.20/1.7.5. This affects an unknown part. The manipulation of the argument _uid with an unknown input leads to a command injection vulnerability. CWE is classifying the issue as 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. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Roundcube Webmail before 1.6.21 and 1.7.x before 1.7.6 contains an IMAP command injection vulnerability that allows attackers to inject commands via CRLF in the _uid parameter when messages_cache is enabled. Attackers can lure logged-in victims into opening crafted GET links to mail/show or mail/get, executing IMAP commands that delete messages, change flags, or grant mailbox access via SETACL.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-126813 since 11/11/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1202 for this issue.

Upgrading to version 1.6.21 or 1.7.6 eliminates this vulnerability.

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Productinfo

Type

• Mail Client Software

Vendor

• Roundcube

Name

• Webmail

Version

• 1.6.0
• 1.6.1
• 1.6.2
• 1.6.3
• 1.6.4
• 1.6.5
• 1.6.6
• 1.6.7
• 1.6.8
• 1.6.9
• 1.6.10
• 1.6.11
• 1.6.12
• 1.6.13
• 1.6.14
• 1.6.15
• 1.6.16
• 1.6.17
• 1.6.18
• 1.6.19
• 1.6.20
• 1.7.0
• 1.7.1
• 1.7.2
• 1.7.3
• 1.7.4
• 1.7.5

License

• free

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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