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CVE-2021-38299

31
FAUCET Score

CVE-2021-38299 is an Incorrect Access Control vulnerability affecting Spomky Labs Webauthn Framework versions 3.3.x prior to 3.3.4. An attacker controlling a user's system can bypass user presence checks and log into vulnerable services using an attached FIDO2 authenticator. This vulnerability carries a critical CVSS score of 9.8, indicating a network-based attack with low complexity, leading to high confidentiality, integrity, and availability impacts. While there is no evidence of active exploitation, Metasploit, Nuclei, or ExploitDB modules, the CVE has garnered significant community discussion and media coverage, including a recent article linking it to potential PassKey account takeovers.

Impacted Technologies

VendorProductVersion(s)CPE
< 3.2.9CPE matchmatch criteria
cpe:2.3:a:spomky-labs:webauthn_framwork:*:*:*:*:*:*:*:*
>= 3.3.0, < 3.3.4CPE matchmatch criteria
cpe:2.3:a:spomky-labs:webauthn_framwork:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.80%
Probability of exploitation in next 30 days
EPSS Percentile
76.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0180 is in the 64th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

composerpatch availablevia ghsa
Product: web-auth/webauthn-frameworkFixed in: 3.3.4

Vendor Advisories (1)

composerGHSA-6whf-q6p5-84wgcritical

Improper Access Control in Webauthn Framework

Sep 29, 2021

References

github.com / web-auth/webauthn-framework/releases
Release NotesThird Party Advisory
fzi.de / en/news/news/detail-en/artikel/fsa-2021-1-fehlende-ueberpruefung-von-user-presence-in-webauthn-framework
Third Party Advisory