Home/CVE/Saml2 Authentication services for ASP.NET (NuGet package Sustainsys.Saml2) greater than 2.0.0, and less than version 2.5
CVE

CVE-2020-5261

Saml2 Authentication services for ASP.NET (NuGet package Sustainsys.Saml2) greater than 2.0.0, and less than version 2.5

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.

HIGH · CVSS 8.2 EPSS 0.00285
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-294Authentication Bypass by Capture-replay
CWE-294Authentication Bypass by Capture-replay
▤

Affected Products & Versions

1
sustainsys saml2>= 2.0.0 and < 2.5.0
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
NuGet Sustainsys.Saml2 HIGH fixed in 2.5.0
▣

Scoring & Timeline

8.2
HIGH · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD25 Mar 2020 · 02:15 AM
CVSS VectorCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/Sustainsys/Saml2/commit/e58e0a1aff2b1ead6aca080b7cdced55ee6d5241PatchThird Party Advisory
https://github.com/Sustainsys/Saml2/issues/711Issue TrackingThird Party Advisory
https://github.com/Sustainsys/Saml2/security/advisories/GHSA-g6j2-ch25-5mmvThird Party Advisory
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