CVE-2026-85604: Grav before 2.0.18 Remote Code Execution via sort filter

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-04 · updated 2026-09-08
Weakness: CWE-94

Description

Grav before 2.0.18 (affected versions <= 2.0.17) contains a remote code execution vulnerability in the Twig sort filter. The sortFunc wrapper in GravExtension.php hardcodes Twig's isSandboxed argument to false, so unlike |map/|filter/|reduce, |sort accepts a plain function name inside the sandbox; the remaining denylist misses spl_autoload, which performs a PHP include. An authenticated user with only page-write rights (admin.pages or api.pages.write) can supply a crafted payload (e.g., via form frontmatter rendered by the Email plugin) that invokes spl_autoload through the sort filter, resulting in arbitrary PHP execution as the web server user.

Affected products

getgrav grav: before 2.0.18 — fixed in 2.0.18

How to fix

Upgrade to a fixed version: getgrav grav 2.0.18. Check the vendor advisory for mitigations.

References

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