CVE-2026-56700

Grav - Multiple Remote Code Execution Vulnerabilities via Unsafe Unserialize and Command Injection

State: Published
Severity: 9.3 Critical
Published: Jun 30, 2026
Updated: Oct 8, 2026
Reserved: Jun 22, 2026

Description

Grav CMS before 2.0.0-beta.2 contains multiple code-execution vulnerabilities. Three unsafe unserialize() calls - in Scheduler\JobQueue, Framework\Cache\Adapter\FileCache, and Session - deserialize untrusted data without restricting allowed classes, enabling PHP object injection and, via a gadget chain, arbitrary code execution where an attacker controls the serialized input. Additionally, InstallCommand's git clone operation passes the branch, url, and path parameters into a shell command without escaping, allowing OS command injection via plugin/theme installation (which requires admin access). A Twig security blocklist bypass (server-side template injection) is also present. The issues are fixed in 2.0.0-beta.2.

Scores

CVSS	Score	Vector	Source
4.0	9.3 Critical	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	VulnCheck
3.1	9.8 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	VulnCheck

Weaknesses

CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CWE-502 Deserialization of Untrusted Data

Affected Products

Product	Versions
GravGrav	before 2.0.0-beta.2Affected 2.0.0-beta.2Not affected

References

GitHub Security Advisory (GHSA-vj3m-2g9h-vm4p)vendor-advisory
VulnCheck Advisory: Grav - Multiple Remote Code Execution Vulnerabilities via Unsafe Unserialize and Command Injectionthird-party-advisory

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