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OS Command InjectionWeakness · CWE-78

CVE-2026-56700

CRITICAL · 9.8 CVSS v3.1 Published 2026-06-30
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Grav CMS before 2.0.0-beta.2 contains critical vulnerabilities: three unsafe unserialize() calls in Scheduler\JobQueue, Framework\Cache\Adapter\FileCache, and Session accept untrusted serialized data without class restrictions, enabling PHP object injection and gadget-chain-based RCE; InstallCommand's git clone operation has OS command injection via unescaped parameters (requires admin access); and a Twig blocklist bypass allows server-side template injection.

MitigationUpgrade to Grav CMS 2.0.0-beta.2 or later immediately; until patched, strictly limit admin access, disable plugin/theme installation, and monitor for compromise indicators.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Grav CMS version
    Locate the version file or header in the Grav installation (commonly in system/src/Grav/Common/Grav.php or system/defines.php), or access the admin dashboard and check the About/System Information page
    Affected if The installed version is any version prior to 2.0.0-beta.2 (for example, 1.x.x, 2.0.0-beta.1, or 2.0.0-alpha versions)
  2. Confirm admin access exposure
    Check if the Grav admin panel is accessible by attempting to access the /admin path or by reviewing web server configuration for admin route exposure
    Affected if The admin panel is accessible to untrusted users (required for the OS command injection via InstallCommand git clone)
  3. Verify Scheduler component is enabled
    Check if the Scheduler plugin/feature is active by examining the configuration in user/config/system.yaml or by listing active plugins in the Grav installation
    Affected if Scheduler is enabled and the version is below 2.0.0-beta.2 (one unsafe unserialize location)
  4. Verify FileCache is in use
    Review the cache configuration in user/config/system.yaml to confirm the FileCache adapter is configured (cache adapter set to file)
    Affected if FileCache adapter is configured and the version is below 2.0.0-beta.2 (another unsafe unserialize location)
  5. Verify Twig template rendering is accessible
    Check if Twig templates can be rendered through user-accessible endpoints or the admin interface, and identify if custom Twig templates exist in user/themes or user/pages
    Affected if Custom Twig templates can be edited or injected and the version is below 2.0.0-beta.2 (enables SSTI via blocklist bypass)

The environment is affected if Grav CMS version is below 2.0.0-beta.2, with higher risk if the admin panel is exposed or if custom Twig templates are usable.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Grav CMS 2.0.0-beta.2 or later immediately; until patched, strictly limit admin access, disable plugin/theme installation, and monitor for compromise indicators.

Recommended fix High confidence

2.0.0-beta.2

  1. 1. Back up the entire Grav CMS installation including all files, plugins, themes, and the database if used
  2. 2. Review current plugins and themes for compatibility with Grav 2.0.0-beta.2
  3. 3. If using a package manager (Composer), run `composer require gravcms/grav:2.0.0-beta.2` or download the release from the official Grav GitHub repository
  4. 4. If upgrading manually, download the 2.0.0-beta.2 release package from github.com/getgrav/grav
  5. 5. Replace the core Grav files with the new version, preserving configuration and user content
  6. 6. Clear all cache directories (cache/, tmp/, logs/) after upgrade
  7. 7. Verify the installation by accessing the admin panel and checking that all plugins/themes function correctly
  8. 8. Test that the vulnerable unserialize() calls and InstallCommand are no longer exploitable
Caveat Beta software - may contain breaking changes or stability issues; test thoroughly in staging before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-56700 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data