Skip to main content
VulnerabilityPublished

craftcms/cms · Craft CMS: Passkey login accepts replayed WebAuthn assertions

Affects craftcms/cmsSource GCVE Database

0

CVSS 9.1 Critical : upgrade to 5.10.5 as a priority.

Data as of 8 Aug 2026, 15:44 UTC

CVSS 4.0 base score
9.1Critical
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.10.5
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

What to do

Upgrade craftcms/cms to 5.10.5.

Affected software

ProductAffectedFixed in
Packagistcraftcms/cmsAffected
  • >=5.0.0-RC1 <5.10.5
Fixed in
  • 5.10.5

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available for this vulnerability. Users should apply the official fix provided by Craft CMS to ensure that the updated credential counter is properly persisted after each WebAuthn assertion validation, preventing replay attacks. Until patched, avoid exposing passkey login request bodies in logs, proxies, or other channels that could be accessed by attackers.

Description

Craft CMS passkey login functionality improperly handles WebAuthn assertions by accepting replayed requestOptions and failing to update the stored credential counter. This allows an attacker who captures a successful passkey login request body to replay it and create additional authenticated sessions for the victim user, effectively bypassing WebAuthn's replay protections and enabling account/session takeover.

References

Community reviews

Loading reviews…