GitHub Advisoryadvisory · Packagist

GHSA-g8r4-p96j-xfxc Grav's Twig processing allowing dangerous PHP functions by default

HIGH Published 2021-04-16 Modified 2022-08-11 Official page ↗
Aliases
CVE-2021-29440
Ecosystem
Packagist
Packages
getgrav/grav
Severity
High
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H
Weaknesses
CWE-94
Reviewed
2021-04-13

Affected packages

• Packagist getgrav/grav: < 1.7.11 → fixed in 1.7.11

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.

Related

Alias · CVE (1)

Weakness · CWE (1)

  • CWE-94 Improper Control of Generation of Code weakness

References