CVE-2026-56700
CVE-2026-56700 is a critical-severity vulnerability with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- CVSS v4: 9.3
- EPSS exploit prediction: 2% (74th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-78
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-56700?
- 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.
- How severe is CVE-2026-56700?
- CVE-2026-56700 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-56700 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-56700?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- When was CVE-2026-56700 published?
- CVE-2026-56700 was published on 2026-06-30 and last updated on 2026-07-01.
References
- https://github.com/getgrav/grav/security/advisories/GHSA-vj3m-2g9h-vm4p
- https://www.vulncheck.com/advisories/grav-multiple-remote-code-execution-vulnerabilities-via-unsafe-unserialize-and-command-injection
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