# CVE-2026-113386: Roundcube Webmail IMAP command injection in mail actions

Source: https://junglewise.ai/threats/cve-2026-113386-roundcube-webmail-before-1-6-20-and-1-7-x-before-1-7-5-are  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-20. Updated: 2026-10-20  
License: CC BY 4.0 with a link back

CVE-2026-113386 · Severity: high · CVSS 7.1 · Published 2026-10-20

Roundcube Webmail is a web-based email client used to access email from any browser. An authenticated attacker can inject IMAP commands by inserting special characters into email parameters, allowing them to execute arbitrary IMAP commands on the mail server and potentially access unauthorized email data.

Technologies: [Roundcube Webmail](https://junglewise.ai/threats/technologies/webmail). Vendors: [Roundcube](https://junglewise.ai/threats/vendors/roundcube).

## Quick answers

**Is CVE-2026-113386 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-113386 being exploited in the wild.

**How severe is CVE-2026-113386?** High severity, with a CVSS score of 7.1, published 20 October 2026.

**Which products and versions are affected?** Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5.

**Is there a fix for CVE-2026-113386?** Yes: fixed in Roundcube Webmail 1.6.20, 1.7.5. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-113386 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-113386?** 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 1.6.20, 1.7.5

## Technical details

The vulnerability is an IMAP command injection flaw in the mail/headers and mail/viewsource actions, where CRLF sequences injected into the _uid parameter bypass input validation. An authenticated remote attacker can craft malicious requests to execute arbitrary IMAP commands against the connected mail server. The fix involves proper sanitization of the _uid parameter to strip or reject CRLF characters.

## Affected products

- Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5

## Timeline

- 2026-10-20: disclosed
- 2026-10-19: patched

## References

- [https://bugs.debian.org/1151279](https://bugs.debian.org/1151279)
- [https://github.com/roundcube/roundcubemail/commit/004adaaeca4f6799715a54d12e3f657f19efcc9a](https://github.com/roundcube/roundcubemail/commit/004adaaeca4f6799715a54d12e3f657f19efcc9a)

## Related threats

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- [Roundcube Webmail uncontrolled resource consumption in CSS proxy](https://junglewise.ai/threats/cve-2026-114731-roundcube-webmail-before-1-6-20-and-1-7-x-before-1-7-5-is)
- [Roundcube Webmail server-side request forgery filter bypass](https://junglewise.ai/threats/cve-2026-114730-roundcube-webmail-1-6-14-before-1-6-20-and-1-7-0-before-1-7-5-is)
- [Roundcube Webmail content blocking bypass via SVG SMIL](https://junglewise.ai/threats/cve-2026-114729-roundcube-webmail-before-1-6-20-and-1-7-x-before-1-7-5-is)
- [Roundcube Webmail remote content blocking bypass in CSS FuncIRI handling](https://junglewise.ai/threats/cve-2026-114728-roundcube-webmail-before-1-6-20-and-1-7-x-before-1-7-5-is)