---
id: "CVE-2026-114725"
kind: "vulnerability"
aliases: ["CVE-2026-114725"]
title: "Roundcube Webmail: header injection lets logged-in users add mail headers"
severity: "medium"
cvss: 5.0
epss: 0.00286
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["mail-server", "package", "roundcube", "self-hosted", "webmail"]
not_affected_if: ["already-patched", "no-user-accounts"]
published_at: "2026-10-22T02:17:00+00:00"
first_seen_at: "2026-10-23T21:57:30+00:00"
updated_at: "2026-10-25T04:29:25+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-114725", "first_seen_at": "2026-10-23T21:57:30+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-114725", "first_seen_at": "2026-10-24T07:15:52+00:00"}]
---

# Roundcube Webmail: header injection lets logged-in users add mail headers

Roundcube Webmail does not strip newlines from the References, In-Reply-To, Message-ID and From fields when sending mail, so a logged-in user can inject extra headers into outgoing messages. The attacker gets to shape the headers of mail sent through the server, which can be used to spoof or manipulate messages.

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

## How to check

- Check the installed version with `grep -i "RCMAIL_VERSION" program/include/iniset.php` in the Roundcube install directory
- Compare against the fixed releases: any `1.6.x` below `1.6.20` or any `1.7.x` below `1.7.5` is exposed

## Fix

- Upgrade Roundcube Webmail to `1.6.20` on the 1.6 branch or `1.7.5` on the 1.7 branch
- Apply the upstream commit "Fix mail header injection via References/In-Reply-To/Message-ID/From parameters" if you cannot upgrade yet

## Timeline

- 2026-10-23T21:57:30+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-114725
- 2026-10-24T07:15:52+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-114725

## From the sources

Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by a mail header injection vulnerability. rcmail_sendmail stripped newline characters only from the Subject and Organization headers, leaving other header values taken from request parameters unsanitized, so a remote authenticated attacker could inject arbitrary headers into an outgoing message via the References, In-Reply-To, Message-ID and From parameters. Upstream fixed this in the commit “Fix mail header injection via References/In-Reply-To/Message-ID/From parameters”, which normalizes whitespace in every string header value.

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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_