Is CVE-2026-126813 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-126813 being exploited in the wild.

How severe is CVE-2026-126813?

Medium severity, with a CVSS score of 6.8, published 11 November 2026.

Which products and versions are affected?

Roundcube Webmail before 1.6.21 and 1.7.x before 1.7.6.

Is there a fix for CVE-2026-126813?

Yes: fixed in Roundcube Webmail 1.6.21, 1.7.6. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-126813 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-126813?

Check whether you run Roundcube Webmail at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-126813: Roundcube Webmail IMAP command injection in message cache

CVE-2026-126813 · Severity: medium · CVSS 6.8 · Published 2026-11-11

Roundcube Webmail is a web-based email client that connects to IMAP mail servers. An attacker can inject IMAP commands through specially crafted links that trick logged-in users into opening them, allowing the attacker to delete emails, change message flags, or modify mailbox permissions without the user's knowledge.

Technologies: Roundcube Webmail. Vendors: Roundcube.

Quick answers

Is CVE-2026-126813 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-126813 being exploited in the wild.
How severe is CVE-2026-126813?: Medium severity, with a CVSS score of 6.8, published 11 November 2026.
Which products and versions are affected?: Roundcube Webmail before 1.6.21 and 1.7.x before 1.7.6.
Is there a fix for CVE-2026-126813?: Yes: fixed in Roundcube Webmail 1.6.21, 1.7.6. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-126813 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-126813?: Check whether you run Roundcube Webmail at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: Roundcube Webmail 1.6.21, 1.7.6

Technical details

The vulnerability is an IMAP command injection flaw in the _uid parameter when messages_cache is enabled. A regex pattern failure allows CRLF characters to bypass validation in rcube_imap_generic.php, letting attackers inject arbitrary IMAP commands. The attack requires the victim to click a malicious GET link to the mail/show or mail/get endpoint while logged in.

Affected products

Roundcube Roundcube Webmail before 1.6.21 and 1.7.x before 1.7.6

Timeline

2026-11-11: disclosed

References

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