What is the CVSS score of CVE-2021-47812?

CVE-2021-47812 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.2%.

Which versions of PHP are affected by CVE-2021-47812?

Organizations using GravCMS 1.10.7 face critical risk from CVE-2021-47812, a missing authorization vulnerability rated CVSS 9.8.

Is there a public PoC exploit available for CVE-2021-47812?

Yes, a public proof-of-concept exploit is available for CVE-2021-47812. Prioritise patching immediately. EPSS: 0.2%.

How to fix or mitigate CVE-2021-47812?

Within 24 hours: Identify all affected systems and apply vendor patches immediately. Monitor vendor channels for patch availability.

PHP CVE-2021-47812

CRITICAL

Missing Authorization (CWE-862)

2026-01-16 disclosure@vulncheck.com

PHP Grav

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:54 vuln.today

PoC Detected

Feb 02, 2026 - 16:16 vuln.today

Public exploit code

CVE Published

Jan 16, 2026 - 00:16 nvd

CRITICAL 9.8

DescriptionCVE.org

GravCMS 1.10.7 contains an unauthenticated vulnerability that allows remote attackers to write arbitrary YAML configuration and execute PHP code through the scheduler endpoint. Attackers can exploit the admin-nonce parameter to inject base64-encoded payloads and create malicious custom jobs with system command execution.

AnalysisAI

GravCMS 1.10.7 allows unauthenticated remote attackers to write arbitrary YAML configuration files, leading to full server compromise through admin account creation or code execution.

Technical ContextAI

GravCMS 1.10.7 exposes an endpoint without authentication checks (CWE-862) that processes user-supplied YAML content and writes it to the server's configuration directory. Since Grav uses YAML files for user accounts and system config, this enables creating admin accounts.

RemediationAI

Upgrade GravCMS immediately. Restrict write access to configuration directories at the web server level.

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CVE-2021-47812 vulnerability details – vuln.today

Back

PHP CVE-2021-47812

Severity by source

CVSS VectorNVD

Lifecycle Timeline

DescriptionCVE.org

AnalysisAI

Technical ContextAI

RemediationAI

More from same product – last 7 days

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External POC / Exploit Code