CVE-2026-30964 is a medium-severity (CVSS 5.4) CWE-346 vulnerability in web-auth/webauthn-framework. A fix is available for web-auth/webauthn-framework — see the affected versions and patch details below.
Webauthn Framework: allowed_origins collapses URL-like origins to host-only values, bypassing exact origin validation
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-30964.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
web-auth/webauthn-framework🐘web-auth/webauthn-lib🐘web-auth/webauthn-symfony-bundleReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Summary
When allowed_origins is configured, CheckAllowedOrigins reduces URL-like values to their host component and accepts on host match alone. This makes exact origin policies impossible to express: scheme and port differences are silently ignored.
Details
CheckAllowedOrigins stores each configured allowed origin as:
parse_url($allowedOrigin)['host'] ?? $allowedOrigin
and later reduces the received clientDataJSON.origin the same way:
parse_url($C->origin)['host'] ?? $C->origin
If the reduced value matches, the method returns early. As a result, for the normal allowed_origins path, the later HTTPS check is not reached.
This differs from WebAuthn Level 2, which requires verifying that C.origin matches the RP's origin (scheme + host + port), separately from verifying that authData.rpIdHash matches the expected RP ID.
Affected code:
Spec references:
- §7.1 Registering a New Credential
- §7.2 Verifying an Authentication Assertion
- CollectedClientData.origin
PoC
Configuration:
webauthn:
allowed_origins:
- https://login.example.com:8443
allow_subdomains: false
Send a registration or authentication response whose clientDataJSON.origin is:
https://login.example.com:9443
Observed: the response is accepted, because both values are reduced to login.example.com.
Expected: the response should be rejected, because https://login.example.com:8443 and https://login.example.com:9443 are different origins.
Impact
This is an origin validation error (CWE-346) affecting deployments that use allowed_origins. The most practical browser-facing scenario is same-host / different-port origin confusion. In non-browser or custom clients, scheme confusion may also be relevant.
Fix
Fixed in version 5.2.4 by rewriting CheckAllowedOrigins to perform full origin comparison (scheme + host + port) as required by the WebAuthn spec:
- Origins configured with a scheme (e.g.
https://example.com:8443) are now stored and compared as fullscheme://host[:port]values, with default port normalization (443 for HTTPS, 80 for HTTP). - Origins configured without a scheme are still matched by host only, for backward compatibility.
- Subdomain matching now also verifies scheme and port consistency.
See commit b4cd9a43.
Mitigation
Upgrade to web-auth/webauthn-framework (or web-auth/webauthn-lib / web-auth/webauthn-symfony-bundle) >= 5.2.4.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | web-auth/webauthn-framework | ≥ 5.2.0&&< 5.2.4 | 5.2.4composer require web-auth/webauthn-framework:^5.2.4 |
| 🐘Packagist | web-auth/webauthn-lib | ≥ 5.2.0&&< 5.2.4 | 5.2.4composer require web-auth/webauthn-lib:^5.2.4 |
| 🐘Packagist | web-auth/webauthn-symfony-bundle | ≥ 5.2.0&&< 5.2.4 | 5.2.4composer require web-auth/webauthn-symfony-bundle:^5.2.4 |
Affected Products
webauthn framworkspomky-labswebauthn-libspomky-labswebauthn-symfony-bundlespomky-labsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for web-auth/webauthn-framework, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update web-auth/webauthn-framework to 5.2.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-30964 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2026-30964 in your dependencies?
Find it across Packagist, including transitive dependencies.