---
id: "CVE-2026-107147"
kind: "vulnerability"
aliases: ["CVE-2026-107147"]
title: "Roundcube 2FA plugin: spoofed client headers let attackers skip second factor"
severity: "medium"
cvss: 6.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["email", "package", "php", "roundcube", "self-hosted"]
not_affected_if: ["no-ip-whitelist", "plugin-not-installed"]
published_at: "2026-10-27T10:16:54+00:00"
first_seen_at: "2026-10-27T10:31:02+00:00"
updated_at: "2026-10-27T10:31:59+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-107147", "first_seen_at": "2026-10-27T10:31:02+00:00"}]
---

# Roundcube 2FA plugin: spoofed client headers let attackers skip second factor

The twofactor_gauthenticator plugin for Roundcube trusts the Client-IP and X-Forwarded-For headers without validation. An attacker who already has a user's password can spoof a whitelisted IP address and skip the second factor login step.

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

## How to check

- Check whether the `twofactor_gauthenticator` plugin is installed in the Roundcube `plugins/` directory, and which commit or version it is at.
- Check whether the plugin's IP whitelist is configured in its settings; the sources do not name the exact setting, so unknown.

## Fix

- Update `twofactor_gauthenticator` to a build that includes commit `4640889`; the release version is unknown from the sources.
- Until updated, unknown; the sources name no workaround.

## Timeline

- 2026-10-27T10:31:02+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-107147

## From the sources

The twofactor_gauthenticator plugin for Roundcube is vulnerable to 2fa authentication bypass by spoofed client address headers. Due to the lack of validation of the Client-IP and X-Forwarded-For headers, an attacker who obtains user's password can spoof a whitelisted IP address, resulting in the second factor being bypassed.




This issue was fixed in commit 4640889.

---

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