---
id: "CVE-2026-114720"
kind: "vulnerability"
aliases: ["CVE-2026-114720"]
title: "Roundcube Webmail: CRLF in mark action lets attackers run IMAP commands"
severity: "high"
cvss: 7.1
epss: 0.00805
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["imap", "package", "roundcube", "self-hosted", "webmail"]
not_affected_if: ["no-user-accounts", "patched-version"]
published_at: "2026-10-22T02:16:59+00:00"
first_seen_at: "2026-10-23T21:57:30+00:00"
updated_at: "2026-10-25T03:31:45+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-114720", "first_seen_at": "2026-10-23T21:57:30+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-114720", "first_seen_at": "2026-10-24T07:15:52+00:00"}]
---

# Roundcube Webmail: CRLF in mark action lets attackers run IMAP commands

Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 does not filter CRLF sequences in the _flag parameter of the mail/mark action. A logged-in user can inject arbitrary IMAP commands into the mailbox session on the mail server.

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

## How to check

- Check the installed Roundcube version in `CHANGELOG.md` or the `version` value in `program/include/iniset.php`, looking for anything below `1.6.20` or in the `1.7.x` line below `1.7.5`.
- unknown whether the sources give a further check for the injected IMAP path.

## Fix

- Upgrade Roundcube Webmail to `1.6.20` on the 1.6 line or `1.7.5` on the 1.7 line.
- Apply the upstream commit “Fix IMAP command injection via CRLF in `_flag` parameter of mail/mark action”, which rejects flags containing control, whitespace and IMAP-special characters.

## Timeline

- 2026-10-23T21:57:30+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-114720
- 2026-10-24T07:15:52+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-114720

## From the sources

Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by an IMAP command injection vulnerability. A remote authenticated attacker can exploit this via CRLF sequences injected into the _flag parameter of the mail/mark action to execute arbitrary IMAP commands. Upstream fixed this in the commit “Fix IMAP command injection via CRLF in `_flag` parameter of mail/mark action”, which rejects flags containing control, whitespace and IMAP-special characters.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_