Vulnerability · Published Jul 1, 2026 · Assigned by GitHub_M
CVE-2026-55792Craft CMS: Sensitive File Disclosure / Server-Side File Read
Medium 6.0
In plain English
A medium-severity information exposure in cms from craftcms. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Craft CMS is a content management system (CMS). In versions starting from 4.0.0-RC1 and prior to 4.18.0, and 5.0.0-RC1 and above, prior to 5.10.0, the dataUrl() Twig function is included in Craft’s Twig sandbox allowlist, allowing any control panel user granted the utility:system-messages permission to embed a file-reading payload into system email templates. When those emails are sent, the server reads the target file and returns its contents as a base64-encoded data URL embedded in the email body. The .env file, which typically contains the database password, CRAFT_SECURITY_KEY, and third-party API keys, passes all of Craft’s existing dataUrl() protection checks and is fully exfiltrated. Obtaining CRAFT_SECURITY_KEY enables an attacker to forge session tokens and escalate to full admin account takeover. This issue has been fixed in versions 4.18.0 and 5.10.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Packagist | craftcms/cms | 4.18.0 | GHSA-287w-mxq6-x2cp |
| Packagist | craftcms/cms | 5.10.0 | GHSA-287w-mxq6-x2cp |
Affected products (as reported)
Weakness: CWE-200 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
References
- https://github.com/craftcms/cms/security/advisories/GHSA-287w-mxq6-x2cp x_refsource_CONFIRM
- https://github.com/craftcms/cms/pull/18559 x_refsource_MISC