PatchTheCVECVE-2021-39171: Passport-SAML is a SAML 2.0 authentication provider for Passport, the Node.js authentication library
CVE-2021-39171 is a medium-severity flaw (CVSS 5.3) affecting passport-saml. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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 t
Why this priority
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 5.3 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.3% (top 29%) |
| CISA exploited list | No |
| Weakness | CWE-400 |
| Published | 2021-08-27 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-39171?
passport-saml: upgrade to 3.1.0. Exact commands for each OS are on this page.
Is CVE-2021-39171 being exploited?
CVE-2021-39171 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-39171 affect?
CVE-2021-39171 affects passport-saml. Severity is medium (CVSS 5.3). 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 resu
How urgent is CVE-2021-39171?
Priority 41/100. Remotely exploitable, no login, no user action
Software pages
Related CVEs
- CVE-2022-39299 HIGH 7.4 UPGRADE Passport-SAML is a SAML 2.0 authentication provider for Passport, the Node.js authentication library