CVE-2020-5261
Published:March 25, 2020
Updated:May 17, 2026
Saml2 Authentication services for ASP.NET (NuGet package Sustainsys.Saml2) greater than 2.0.0, and less than version 2.5.0 has a faulty implementation of Token Replay Detection. Token Replay Detection is an important defence in depth measure for Single Sign On solutions. The 2.5.0 version is patched. Note that version 1.0.1 is not affected. It has a correct Token Replay Implementation and is safe to use. Saml2 Authentication services for ASP.NET (NuGet package Sustainsys.Saml2) greater than 2.0.0, and less than version 2.5.0 have a faulty implementation of Token Replay Detection. Token Replay Detection is an important defense measure for Single Sign On solutions. The 2.5.0 version is patched. Note that version 1.0.1 and prior versions are not affected. These versions have a correct Token Replay Implementation and are safe to use.
Affected Packages
sustainsys.saml2 (NUGET):
Affected version(s) >=2.0.0 <2.5.0Fix Suggestion:
Update to version 2.5.0Related Resources (4)
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Contact UsCVSS v4
Base Score:
8.8
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
HIGH
Subsequent System Integrity
HIGH
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.2
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Authentication Bypass by Capture-replay
EPSS
Base Score:
0.29