CVE-2021-39171

Unlimited transforms allowed for signed nodes

HIGH
7.5
CVSS Score
Published: August 27, 2021 at 10:05 PM UTC
Updated: June 17, 2026 at 04:03 AM UTC
2 products affected across 2 vendorsPassport SamlSaml Project Passport Saml

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Severity
HIGH7.5
Exploit prediction
EPSS 1%

Description

Passport-SAML is a SAML 2.0 authentication provider for Passport, the Node.js authentication library. Prior to version 3.1.0, a malicious SAML payload can require transforms that consume significant system resources to process, thereby resulting in reduced or denied service. This would be an effective way to perform a denial-of-service attack. This has been resolved in version 3.1.0. The resolution is to limit the number of allowable transforms to 2.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.1.0
Affected range stops below 3.1.0, so it looks safe — our inference, not a vendor statement
v < 3.1.0
Affected range stops below 3.1.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-400

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