CVE-2026-72781 — craftcms/cms
Fix: craftcms/cms@0b8be15CVE-2026-72781 is a CWE-693 vulnerability in craftcms/cms. A fix is available for craftcms/cms — see the affected versions and patch details below.
Craft CMS 5.0.0-RC1 before 5.10.7 Remote Code Execution via Twig Sandbox Escape
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-72781.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
craftcms/cms🐘craftcms/cmsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
The Twig sandbox mechanism in Craft CMS is configured to allow dangerous functionality from the Yii framework, leading to authenticated RCE in a manner similar to previously disclosed vulnerabilities.
The Twig sandbox in Craft CMS works by implementing Twig's SecurityPolicyInterface. The resulting SecurityPolicy class implements the checkMethodAllowed and checkPropertyAllowed methods of the interface. The implementations compare whether the called method or property is in a configured allowlist or is marked with the AllowedInSandbox attribute.
Additionally, SecurityPolicy allows the allowlisting of whole classes, which is shorthand for allowing all methods and properties of that class to be called. Both the allowlists for tags, filters, variables, methods, properties, and classes, as well as the AllowedInSandbox attribute mechanism, are preconfigured by Craft CMS to allow user-defined templates to use core functionality unimpeded. Additionally, Craft CMS project developers can add more to the allowlists or mark their custom methods and so on as safe with AllowedInSandbox.
The SecurityPolicy class's allowlisting mechanism is potentially dangerous, as it allows all methods and properties on an object of the allowed class. This means that the checked object can be a subclass and be allowed. And it means that the allowed methods and properties can be defined on any class of the class hierarchy of the object, which does not have to be the allowed class itself.
Craft CMS uses the AllowedInSandbox attribute to mark the ElementInterface as safe. The Element class implements this interface and is the base class for many relevant model classes in Craft CMS, like Entry, User, Asset and so on. Additionally, Element extends the craft\base\Component class. Going up the class hierarchy of craft\base\Component, eventually the class yii\base\Component is reached, which is located in the Yii framework used by CraftCMS. yii\base\Component is known to contain a dangerous arbitrary function call gadget which leads to previously disclosed RCE vulnerabilities in Craft CMS (GHSA-255j-qw47-wjh5, GHSA-2fph-6v5w-89hh, GHSA-7jx7-3846-m7w7, GHSA-qrgm-p9w5-rrfw). Due to lax class allowlisting, this function-call gadget is allowed in the Twig sandbox. This allows sandboxed Twig templates to use known payloads based on the function-call gadget to achieve RCE.
Impact
An authenticated attacker with permission to access the control panel can render a malicious Twig template and gain RCE, even if the Twig sandbox is enabled through enableTwigSandbox().
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | craftcms/cms | ≥ 5.0.0-RC1&&< 5.10.7 | 5.10.7composer require craftcms/cms:^5.10.7 |
| 🐘Packagist | craftcms/cms | ≥ 4.0.0-RC1&&< 4.18.3 | 4.18.3composer require craftcms/cms:^4.18.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/cms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update craftcms/cms to 5.10.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-72781 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-72781 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-72781. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-72781 in your dependencies?
O3 Security finds CVE-2026-72781 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.