passport-wsfed-saml2 Has SAML Authentication Bypass via Attribute Smuggling

published 2025-05-06 18 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-13640 , GHSA-8gqj-226h-gm8r

cvss: 8.6; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits: 0; none known

passport-wsfed-saml2 provides passport strategy for both WS-fed and SAML2 protocol. A vulnerability present starting in version 3.0.5 up to and including version 4.6.3 allows an attacker to impersonate any user during SAML authentication by tampering with a valid SAML response. This can be done by adding attributes to the response. Users are affected specifically when the service provider is using `passport-wsfed-saml2` and a valid SAML Response signed by the Identity Provider can be obtained. Version 4.6.4 contains a fix for the vulnerability.

Patch / fix

fixed in 2 links 1

npm passport-wsfed-saml2 4.6.4
auth0 passport-wsfed-saml2 4.6.4

github.com/auth0/passport-wsfed-saml2@e5cf3cc commit

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 18 mo ago (2025-05-07)

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.6	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA	4.0	8.6	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem	package	affected	fixed in
npm	passport-wsfed-saml2	>=3.0.5, <4.6.4	4.6.4

Affected products

auth0 passport-wsfed-saml2

Classification

Weakness

CWE-287 Improper Authentication
CWE-290 Authentication Bypass by Spoofing

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary