CVE-2026-55792

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.

EPSS — Exploit Prediction

0.0027

Probability of exploitation

0.18%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-200 CWE-200

References

Other References

https://github.com/craftcms/cms/pull/18559 https://github.com/craftcms/cms/security/advisories/GHSA-287w-mxq6-x2cp https://github.com/craftcms/cms/pull/18559

Frequently Asked Questions

What is CVE-2026-55792? +

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.

How do I check if I'm vulnerable to CVE-2026-55792? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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