Open-Source Security Intelligence

Know every vulnerability
before 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.

Search

GHSA-g8r4-p96j-xfxc

HighCVSS 8.4 / 10
Published Apr 16, 2021·Last modified May 4, 2026
Affected Components(0)

No affected components available

Description

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.

Patches

The issue was addressed by preventing dangerous functions from being called in Twig templates. A configuration option has been added to manually allow arbitrary PHP functions (system.twig.safe_functions) and filters (system.twig.safe_filters).

Futures major versions of Grav may disable this functionality by default.

Workarounds

Blocking access to the /admin path from untrusted sources will reduce the probability of exploitation.

References

  • https://portswigger.net/research/server-side-template-injection
  • https://blog.sonarsource.com/grav-cms-code-execution-vulnerabilities

For more information

If you have any questions or comments about this advisory, you can contact:

  • The original reporters, by sending an email to vulnerability.research [at] sonarsource.com;
  • The maintainers, by opening an issue on this repository.
Risk Scores
Base Score
8.4

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 high-level or administrative privileges. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. 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.

Threat Intelligence
7.7

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Browse More

Scan your project

Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.

Checkout DevGuard