---
id: "CVE-2026-128335"
page: "https://infrastack.ai/live/CVE-2026-128335"
kind: "vulnerability"
aliases: ["CVE-2026-128335"]
title: "Contao: existing sessions survive two-factor authentication changes"
severity: "low"
cvss: 3.7
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["contao", "package", "php", "self-hosted"]
not_affected_if: ["no-two-factor-users", "patched-version"]
published_at: "2026-11-13T10:18:13+00:00"
first_seen_at: "2026-11-13T10:47:34+00:00"
updated_at: "2026-11-13T10:58:56+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-128335", "first_seen_at": "2026-11-13T10:47:34+00:00"}]
exploit_sources: []
---

# Contao: existing sessions survive two-factor authentication changes

Link for people: https://infrastack.ai/live/CVE-2026-128335 (this .md is for agents)

Contao does not end existing user sessions when two-factor authentication is turned on or off for an account. An attacker who already holds a session cookie keeps access after the account owner changes their 2FA settings.

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

## Fix

- Contao `5.3.54` or later for the 5.3 line
- Contao `5.7.17` or later for the 5.4 line
- Contao `6.0.6` or later for the 6.0 line

## Timeline

- 2026-11-13T10:47:34+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-128335

## Documents

- [advisory] Vendor advisory: github.com https://github.com/contao/contao/security/advisories/GHSA-5mg3-mv6j-57wc
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/contao-before-5.3.54-5.7.17-and-6.0.6-session-invalidation-failure-on-2fa-change
- [fix] Patch: github.com https://github.com/contao/contao/commit/843da308056402d94ae2dbb999959f9e2ce71fe1
- [fix] Release notes: github.com https://github.com/contao/contao/releases/tag/5.3.54
- [fix] Patch: github.com https://github.com/contao/contao/commit/7618a5757347a30168139e74c7b326e3e296059d
- [fix] Release notes: github.com https://github.com/contao/contao/releases/tag/6.0.6
- [fix] Release notes: github.com https://github.com/contao/contao/releases/tag/5.7.17
- [fix] Patch: github.com https://github.com/contao/contao/commit/7e7c821ce6c41c02ae85b3d9f8eff5039de3fe1e

## From the sources

Contao 4.6.0 before 5.3.54, 5.4.0-RC1 before 5.7.17, and 6.0.0-RC1 before 6.0.6 fails to invalidate existing user sessions when two-factor authentication is enabled or disabled. Because Contao\User::isEqualTo() and serialized session data omit two-factor state, attackers already holding a session keep it after the owner changes 2FA settings.

---

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