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CVE-2020-27198 ESP Session Hijack due to common credentials


Kemp Reference PD-15788

Where multiple users share credential properties, a vulnerability in the handling of User Sessions in LoadMaster Edge Security Pack (ESP) could enable one authenticated user to inadvertently take over another authenticated user's session.


Where two users share credential properties including a specific matching portion of the username as well as the same password, simultaneous logins can result in one user accessing the other user's session. This could result in data being inadvertently accessed by a user.

Affected Products

The following products are affected by this vulnerability:

LoadMasters utilising ESP running LMOS versions 7.2.51, 7.2.50, using Client-Side Forms Based Authentication

Not affected :

LoadMasters not utilising Edge Security Pack (ESP)

LoadMasters utilizing ESP but not using Client-Side Forms Based Authentication

LoadMasters running LMOS version or lower

LoadMasters running LMOS version LMOS LMOS 7.2.52+(GA)


If you are utilising ESP and using Client-Side Forms Based Authentication while running LMOS versions 7.2.51, 7.2.50 or, please upgrade the LoadMaster Firmware to 7.2.53 (General Availability Release) or (Long Term Stable Release).

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user user

Mitigation? Fix?



Nick Smylie

Hi @infra

We are going to work on this to make it a bit clearer. However the correct way to mitigate against this is to use one of our current firmware versions of 7.2.53 or