---
id: "CVE-2026-126813"
page: "https://infrastack.ai/live/CVE-2026-126813"
kind: "vulnerability"
aliases: ["CVE-2026-126813"]
title: "Roundcube Webmail: crafted links inject IMAP commands into mailboxes"
severity: "high"
cvss: 7.4
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["imap", "package", "roundcube", "self-hosted", "webmail"]
not_affected_if: ["managed-hosting", "messages_cache-disabled"]
published_at: "2026-11-11T21:16:45+00:00"
first_seen_at: "2026-11-11T21:29:09+00:00"
updated_at: "2026-11-11T21:30:47+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126813", "first_seen_at": "2026-11-11T21:29:09+00:00"}]
exploit_sources: []
---

# Roundcube Webmail: crafted links inject IMAP commands into mailboxes

Link for people: https://infrastack.ai/live/CVE-2026-126813 (this .md is for agents)

Roundcube Webmail before 1.6.21 and 1.7.x before 1.7.6 accepts CRLF characters in the _uid parameter when messages_cache is enabled, so IMAP commands can be injected. An attacker who lures a logged-in user to a crafted GET link to mail/show or mail/get can delete messages, change flags, or grant mailbox access via SETACL.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Roundcube version in the footer of the login page or in `CHANGELOG` and `program/include/iniset.php` in the install directory.
- Check whether `messages_cache` is enabled in `config/config.inc.php` (`$config['messages_cache']`).

## Fix

- Roundcube Webmail `1.6.21` for the 1.6 branch.
- Roundcube Webmail `1.7.6` for the 1.7 branch.

## Timeline

- 2026-11-11T21:29:09+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-126813

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/roundcube-webmail-before-1.6.21-and-1.7.6-imap-command-injection-via-uid
- [fix] Patch: github.com https://github.com/roundcube/roundcubemail/commit/2ea63692178cab5cea486c7c630901b7f6852c80
- [fix] Patch: github.com https://github.com/roundcube/roundcubemail/commit/4cb1cf106b9ca5d465ed4924f2fab5d5108edfeb
- [fix] Patch: github.com https://github.com/roundcube/roundcubemail/commit/d1dda13597ceed9df49d434a8d88b758bcf6ef5c
- [fix] Release notes: github.com https://github.com/roundcube/roundcubemail/releases/tag/1.6.21
- [fix] Release notes: github.com https://github.com/roundcube/roundcubemail/releases/tag/1.7.6

## From the sources

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.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_