Contao up to 5.3.53/5.7.16/6.0.5 Session Data Contao\User::isEqualTo improper authentication

Summaryinfo

A vulnerability, which was classified as critical, has been found in Contao up to 5.3.53/5.7.16/6.0.5. Affected by this vulnerability is the function Contao\User::isEqualTo of the component Session Data. The manipulation leads to improper authentication. This vulnerability is uniquely identified as CVE-2026-128335. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Contao up to 5.3.53/5.7.16/6.0.5. This issue affects the function Contao\User::isEqualTo of the component Session Data. The manipulation with an unknown input leads to a improper authentication vulnerability. Using CWE to declare the problem leads to CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-128335 since 11/13/2026. The exploitation is known to be easy. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

Upgrading to version 5.3.54, 5.7.17 or 6.0.6 eliminates this vulnerability.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• Contao

Version

• 5.3.0
• 5.3.1
• 5.3.2
• 5.3.3
• 5.3.4
• 5.3.5
• 5.3.6
• 5.3.7
• 5.3.8
• 5.3.9
• 5.3.10
• 5.3.11
• 5.3.12
• 5.3.13
• 5.3.14
• 5.3.15
• 5.3.16
• 5.3.17
• 5.3.18
• 5.3.19
• 5.3.20
• 5.3.21
• 5.3.22
• 5.3.23
• 5.3.24
• 5.3.25
• 5.3.26
• 5.3.27
• 5.3.28
• 5.3.29
• 5.3.30
• 5.3.31
• 5.3.32
• 5.3.33
• 5.3.34
• 5.3.35
• 5.3.36
• 5.3.37
• 5.3.38
• 5.3.39
• 5.3.40
• 5.3.41
• 5.3.42
• 5.3.43
• 5.3.44
• 5.3.45
• 5.3.46
• 5.3.47
• 5.3.48
• 5.3.49
• 5.3.50
• 5.3.51
• 5.3.52
• 5.3.53
• 5.7.0
• 5.7.1
• 5.7.2
• 5.7.3
• 5.7.4
• 5.7.5
• 5.7.6
• 5.7.7
• 5.7.8
• 5.7.9
• 5.7.10
• 5.7.11
• 5.7.12
• 5.7.13
• 5.7.14
• 5.7.15
• 5.7.16
• 6.0.0
• 6.0.1
• 6.0.2
• 6.0.3
• 6.0.4
• 6.0.5

Website

• Product: https://github.com/contao/contao/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion