CVE-2020-5261
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.
Does this matter?
Lower severity and a low EPSS score (1.50%). Track it; it rarely justifies an emergency change on its own.
Description
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.
- CVSS 3.1
- 6.8 MEDIUMCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 1.50% probability · 74th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-294
- Affected
- sustainsys/saml2
- Source
- security-advisories@github.com
EPSS 1.5% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/Sustainsys/Saml2/commit/e58e0a1aff2b1ead6aca080b7cdced55ee6d5241Patch, Third Party Advisory
- https://github.com/Sustainsys/Saml2/issues/711Issue Tracking, Third Party Advisory
- https://github.com/Sustainsys/Saml2/security/advisories/GHSA-g6j2-ch25-5mmvThird Party Advisory
- https://github.com/Sustainsys/Saml2/commit/e58e0a1aff2b1ead6aca080b7cdced55ee6d5241Patch, Third Party Advisory
- https://github.com/Sustainsys/Saml2/issues/711Issue Tracking, Third Party Advisory
- https://github.com/Sustainsys/Saml2/security/advisories/GHSA-g6j2-ch25-5mmvThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.