Security readout for executives and security teams
Plain-English summary
This issue can let an attacker make a SAML login service spend excessive resources processing a malicious authentication message. The expected business impact is service degradation or outage for affected SSO flows, not data theft or account takeover based on the provided sources.
Executive priority
Treat as a moderate availability risk for systems relying on SAML SSO. Patch promptly where vulnerable versions protect public or business-critical login paths, but the provided evidence does not indicate confidentiality compromise or known active exploitation.
Technical view
Passport-SAML before 3.1.0 did not limit the number of transforms allowed for signed nodes. A malicious SAML payload could force expensive transform processing and reduce or deny service. Version 3.1.0 fixes this by limiting allowable transforms to two.
Likely exposure
Exposure is likely limited to Node.js applications using node-saml/passport-saml versions earlier than 3.1.0 for SAML authentication. Internet-facing SSO endpoints are the main concern. The source bundle does not identify specific downstream products or CPEs.
Exploitation context
The CVSS vector indicates network access, low complexity, no privileges, and no user interaction. The impact is availability only. The CVE is not listed as KEV in the provided bundle, and no cited source here confirms active exploitation.
Researcher notes
This is CWE-400 resource consumption with CVSS 3.1 score 5.3. The important validation question is whether signed-node transform handling comes from passport-saml below 3.1.0 in a reachable SAML flow. Avoid assuming broader SAML library impact without dependency evidence.
Mitigation direction
- Upgrade passport-saml to version 3.1.0 or later.
- Confirm the deployed lockfile resolves passport-saml at a fixed, non-vulnerable version.
- Prioritize applications with public SAML login endpoints.
- Review the GitHub advisory before choosing any alternate remediation path.
Validation and detection
- Inventory applications using node-saml/passport-saml.
- Check package manifests and lockfiles for versions below 3.1.0.
- Confirm production deployments run the remediated dependency version.
- Review SAML authentication service monitoring for availability anomalies.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-400: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-39171 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/node-saml/passport-saml/security/advisories/GHSA-5379-r78w-42h2CVE reference · x_refsource_CONFIRM
- https://github.com/node-saml/passport-saml/pull/595CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.