Webauthn has a User Verification Downgrade via Default-Open ClientOverridePolicy

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

2.1 · CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary In version 5.3.0 of the Symfony bundle, Webauthn\Bundle\Policy\ClientOverridePolicy defaulted to allowing all client overrides, including userVerification. A client could send {"userVerification": "discouraged"} in the assertion or attestation options request to override a server-configured userVerification: required, causing the emitted WebAuthn options to instruct the authenticator to skip user verification. The CheckUserVerification ceremony step then read the same downgraded options and skipped its check. Affected versions - Vulnerable: 5.3.0 - Patched: 5.3.1 5.3.0 was released on 2026-05-01 and 5.3.1 was published roughly 18 hours later, on 2026-05-02. Practical exposure window was minimal. Note on earlier 5.x versions Versions 5.0.0 to 5.2.x did not ship ClientOverridePolicy (introduced in 5.3.0), so the exact code path described above does not apply. However, on those versions the ProfileBasedRequestOptionsBuilder and ProfileBasedCreationOptionsBuilder already passed…

Published by the source

7 May 2026, 21:05 UTC

Last modified by the source

7 May 2026, 21:05 UTC

Source last checked

26 Oct 2026, 14:40 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-h4fw-6r7f-w494

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# Patch Next advisory brief: GHSA-h4fw-6r7f-w494

Advisory: Webauthn has a User Verification Downgrade via Default-Open ClientOverridePolicy
IDs: GHSA-h4fw-6r7f-w494
Record: https://patchnext.com/advisories/ghsa-h4fw-6r7f-w494 (revision 1, source checked 26 Oct 2026, 14:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 2.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: web-auth/webauthn-framework 5.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist web-auth/webauthn-framework: affected >= 5.3.0, < 5.3.1; fixed in 5.3.1

## Suggested inspection (read-only)
- Packagist web-auth/webauthn-framework: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on web-auth/webauthn-framework.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-h4fw-6r7f-w494 (GitHub-reviewed advisory GHSA-h4fw-6r7f-w494 lists affected ranges: Packagist web-auth/webauthn-framework >=5.3.0 <5.3.1)

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