CVE-2026-112777 craftcms CVE debrief

Who should care

Defenders responsible for Craft CMS installations should assess exposure and prioritize patching to prevent potential remote code execution and unauthorized access to sensitive data. This includes administrators, security teams, and vulnerability management teams who need to review the affected scope and severity in their environments.

Why it matters

Defenders should prioritize patching Craft CMS installations to prevent potential remote code execution and unauthorized access to sensitive data.

• Potential remote code execution
• Possible reading of .env secrets
• Potential writing of PHP files into the webroot

Technical summary

The vulnerability is caused by a blocklist bypass in the Twig create() function, which allows attackers with template-execution rights to instantiate SplFileObject and read .env secrets or write a PHP file into the webroot for remote code execution. The blocklist bypass occurs because the class-name checks in the Twig create() function are case-sensitive, while PHP class resolution is not. This allows attackers to bypass the blocklist and instantiate arbitrary classes, including SplFileObject, which can be used to read or write files.

Defensive priority

Defenders should prioritize patching Craft CMS installations to prevent potential remote code execution.

Recommended defensive actions

• Patch Craft CMS installations to version 4.18.8 or 5.11.0
• Restrict template-execution rights to trusted users
• Monitor for suspicious activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its CVSS score and vector. The vulnerability was reported by a researcher and has been publicly disclosed. There is no evidence of in-the-wild exploitation at the time of disclosure. However, defenders should verify the affected scope and severity in their environments.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.