# CVE-2026-72780: Craft CMS WebAuthn assertion replay in passkey login

Source: https://junglewise.ai/threats/cve-2026-72780-craft-cms-webauthn-assertion-replay-in-passkey-login  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-11. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-72780 · Severity: medium · CVSS 6.5 · Published 2026-08-11

Craft CMS's passkey login feature fails to properly validate replay protection, allowing attackers to reuse captured login requests to create additional authenticated sessions for victim accounts. If an attacker obtains a single successful login request (which could happen through application logs, debugging proxies, or similar exposure), they can replay it multiple times to gain unauthorized access to the victim's account without needing the actual passkey device.

Technologies: [craftcms/cms (Packagist)](https://junglewise.ai/threats/technologies/craftcms-cms). Vendors: [Packagist](https://junglewise.ai/threats/vendors/packagist).

## Quick answers

**Is CVE-2026-72780 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-72780 being exploited in the wild.

**How severe is CVE-2026-72780?** Medium severity, with a CVSS score of 6.5, published 11 August 2026.

**Which products and versions are affected?** craftcms/cms (Packagist) ECOSYSTEM:introduced=5.0.0-RC1,fixed=5.10.5.

**Is there a fix for CVE-2026-72780?** Yes. craftcms/cms (Packagist): upgrade to 5.10.5 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-72780 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-72780?** Check whether you run craftcms/cms (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- craftcms/cms (Packagist): upgrade to 5.10.5 or later

  ```sh
  composer require craftcms/cms:^5.10.5
  ```


## Technical details

Craft CMS's passkey login endpoint (/actions/users/login-with-passkey) accepts WebAuthn requestOptions from unauthenticated user input and fails to persist the updated credential counter after assertion validation. The vulnerability is a capture-replay flaw (CWE-294): the system accepts the same requestOptions and response multiple times, allowing the attacker to validate assertions against stale credential counters. An attacker with a captured login request body containing requestOptions and response can repost it to the endpoint, bypassing WebAuthn's challenge-response and replay-counter protections. The vulnerability affects Craft CMS versions 5.0.0-RC1 through 5.10.4; version 5.10.5 and later persist updated credential sources to prevent replay attacks. No authentication is required to trigger the replay, only possession of the previously-captured request body.

## Affected products

- Craft CMS 5.0.0-RC1 to before 5.10.5

## Identifiers

- CVE-2026-72780
- GHSA-wg23-69c2-gjc8

## Timeline

- 2026-07-25: disclosed: GitHub Security Advisory GHSA-wg23-69c2-gjc8 published
- 2026-08-11: patched: Craft CMS 5.10.5 released with fix
- 2026-08-11: advisory: CVE-2026-72780 published on NVD

## References

- [https://github.com/craftcms/cms/security/advisories/GHSA-wg23-69c2-gjc8](https://github.com/craftcms/cms/security/advisories/GHSA-wg23-69c2-gjc8)
- [https://www.vulncheck.com/advisories/craft-cms-before-webauthn-assertion-replay-via-login-with-passkey](https://www.vulncheck.com/advisories/craft-cms-before-webauthn-assertion-replay-via-login-with-passkey)

## Related threats

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- [Craft CMS: Arbitrary user password reset leading to administrator account takeover](https://junglewise.ai/threats/cve-2026-72786-craft-cms-arbitrary-user-password-reset-leading-to-administrator)
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