CVE-2026-27128
Craft CMS's race condition in Token Service potentially allows for token usage greater than the token limit
Description
Craft is a content management system (CMS). In versions 4.5.0-RC1 through 4.16.18 and 5.0.0-RC1 through 5.8.22, 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. Versions 4.16.19 and 5.8.23 patch the issue.
INFO
Published Date :
Feb. 24, 2026, 3:16 a.m.
Last Modified :
Feb. 27, 2026, 8:06 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Craft CMS to version 4.16.19 or 5.8.23.
- Apply vendor patches for the token validation service.
- Ensure token operations are atomic to prevent TOCTOU.
- Validate token usage before and after updates.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-27128.
| URL | Resource |
|---|---|
| https://github.com/craftcms/cms/commit/3e4afe18279951c024c64896aa2b93cda6d95fdf | Patch |
| https://github.com/craftcms/cms/security/advisories/GHSA-6fx5-5cw5-4897 | Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-27128 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-27128
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-27128 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-27128 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Feb. 27, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N Added CPE Configuration OR *cpe:2.3:a:craftcms:craft_cms:5.0.0:rc1:*:*:*:*:*:* *cpe:2.3:a:craftcms:craft_cms:5.0.0:-:*:*:*:*:*:* *cpe:2.3:a:craftcms:craft_cms:*:*:*:*:*:*:*:* versions from (excluding) 5.0.0 up to (excluding) 5.8.23 *cpe:2.3:a:craftcms:craft_cms:4.5.0:-:*:*:*:*:*:* *cpe:2.3:a:craftcms:craft_cms:4.5.0:rc1:*:*:*:*:*:* *cpe:2.3:a:craftcms:craft_cms:*:*:*:*:*:*:*:* versions from (excluding) 4.5.0 up to (excluding) 4.16.19 Added Reference Type GitHub, Inc.: https://github.com/craftcms/cms/commit/3e4afe18279951c024c64896aa2b93cda6d95fdf Types: Patch Added Reference Type GitHub, Inc.: https://github.com/craftcms/cms/security/advisories/GHSA-6fx5-5cw5-4897 Types: Third Party Advisory -
New CVE Received by [email protected]
Feb. 24, 2026
Action Type Old Value New Value Added Description Craft is a content management system (CMS). In versions 4.5.0-RC1 through 4.16.18 and 5.0.0-RC1 through 5.8.22, 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. Versions 4.16.19 and 5.8.23 patch the issue. Added CVSS V4.0 AV:N/AC:H/AT:P/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-367 Added Reference https://github.com/craftcms/cms/commit/3e4afe18279951c024c64896aa2b93cda6d95fdf Added Reference https://github.com/craftcms/cms/security/advisories/GHSA-6fx5-5cw5-4897