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CVE-2021-39171

24
FAUCET Score

CVE-2021-39171 describes a denial-of-service vulnerability in Passport-SAML, a Node.js authentication library, affecting versions prior to 3.1.0. An unauthenticated attacker can send a specially crafted SAML payload with excessive transforms, consuming significant system resources and leading to service disruption. This vulnerability has a CVSS score of 7.5 (High) due to its network-based attack vector and high impact on availability. While no active exploitation, public exploits, or significant community discussion have been observed, organizations using affected versions should upgrade to 3.1.0 or later to mitigate the risk.

Impacted Technologies

VendorProductVersion(s)CPE
< 3.1.0CPE matchmatch criteria
cpe:2.3:a:passport-saml_project:passport-saml:*:*:*:*:*:node.js:*:*

CVSS Data

CVSS version used by this source: 3.1

5.3MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
LOW
Exploitability Score
3.9
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.32%
Probability of exploitation in next 30 days
EPSS Percentile
67.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0132 is in the 48th percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
npmpatch availablevia ghsa
Product: passport-samlFixed in: 3.1.0

Vendor Advisories (1)

npmGHSA-5379-r78w-42h2medium

Unlimited transforms allowed for signed nodes

Aug 30, 2021

References

github.com / node-saml/passport-saml/pull/595
PatchThird Party Advisory
github.com / node-saml/passport-saml/security/advisories/GHSA-5379-r78w-42h2
Third Party Advisory