What’s Vulnerable › Vulnerabilities

CVE-2023-34448: Grav Server-side Template Injection (SSTI) via Twig Default Filters

• Severity: high (CVSS 7.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2023-06-14 · updated 2026-06-17
• Weakness: CWE-20

Description

Grav is a flat-file content management system. Prior to version 1.7.42, the patch for CVE-2022-2073, a server-side template injection vulnerability in Grav leveraging the default `filter()` function, did not block other built-in functions exposed by Twig's Core Extension that could be used to invoke arbitrary unsafe functions, thereby allowing for remote code execution. A patch in version 1.74.2 overrides the built-in Twig `map()` and `reduce()` filter functions in `system/src/Grav/Common/Twig/Extension/GravExtension.php` to validate the argument passed to the filter in `$arrow`.

Affected products

• getgrav grav: before 1.7.42 — fixed in 1.7.42

How to fix

Upgrade to a fixed version: getgrav grav 1.7.42. Check the vendor advisory for mitigations.

References

• https://github.com/getgrav/grav/commit/8c2c1cb72611a399f13423fc6d0e1d998c03e5c8
• https://github.com/getgrav/grav/security/advisories/GHSA-whr7-m3f8-mpm8
• https://github.com/twigphp/Twig/blob/v1.44.7/src/Environment.php#L148
• https://huntr.dev/bounties/3ef640e6-9e25-4ecb-8ec1-64311d63fe66/
• https://www.github.com/getgrav/grav/commit/9d6a2dba09fd4e56f5cdfb9a399caea355bfeb83
• https://github.com/getgrav/grav/commit/8c2c1cb72611a399f13423fc6d0e1d998c03e5c8
• https://github.com/getgrav/grav/security/advisories/GHSA-whr7-m3f8-mpm8
• https://github.com/twigphp/Twig/blob/v1.44.7/src/Environment.php#L148
• https://huntr.dev/bounties/3ef640e6-9e25-4ecb-8ec1-64311d63fe66/
• https://www.github.com/getgrav/grav/commit/9d6a2dba09fd4e56f5cdfb9a399caea355bfeb83

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