CVE-2026-27128
Craft CMS Race condition in Token Service potentially allows for token usage greater than the token limit
Impact
A Time-of-Check-Time-of-Use (TOCTOU) race condition exists in Craft CMS’s token validation service for tokens that explicitly set a limited usage. The `getTokenRoute()` method reads a token’s usage count, checks if it’s within limits, then updates the database in separate non-atomic operations. By sending concurrent requests, an attacker can use a single-use impersonation token multiple times before the database update completes. To make this work, an attacker needs to obtain a valid user account impersonation URL with a non-expired token via some other means and exploit a race condition while bypassing any rate-limiting rules in place. For this to be a privilege escalation, the impersonation URL must include a token for a user account with more permissions than the current user. ## References https://github.com/craftcms/cms/commit/3e4afe18279951c024c64896aa2b93cda6d95fdf
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| composer | craftcms/cms | >= 4.5.0-RC1, <= 4.16.18 | 4.16.19 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Craftcms | Craft Cms | after 4.5.0 before 4.16.19 after 5.0.0 before 5.8.23 Versions 4.5.0, 5.0.0 |