PHP
CVE-2021-47812
CRITICAL
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization checks on every request
MITRE ATT&CK
1 technique across 1 tactic: Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | Critical — unauthenticated, network-exploitable, leads to full admin access and arbitrary code execution through Grav's PHP template system. |
| Exploit ScenarioDerived | An attacker sends a POST request to the unprotected endpoint with YAML content defining a new admin account. After creation, the attacker logs in and uses Grav's page editor to inject PHP code, achieving RCE. |
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Alert meAnalysisAIv1 – Mar 12, 2026
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.
Earlier versions of this analysis (1)
Unauthenticated arbitrary YAML file write in GravCMS enables complete server takeover.
RemediationAI
Upgrade GravCMS immediately. Restrict write access to configuration directories at the web server level.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
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.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
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
Lifecycle Timeline
2DescriptionCVE.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.
Executive ViewAI
Organizations using GravCMS 1.10.7 face critical risk from CVE-2021-47812, a missing authorization vulnerability rated CVSS 9.8. Attackers could bypass security controls to gain unauthorized access to protected resources and sensitive data. Proof-of-concept code is publicly available, increasing the risk of exploitation. Organizations should apply vendor updates immediately when available and implement compensating controls in the interim.
Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Exploit-DB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Affected Products (CPE)CVE.org
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The '/common/download_agent_installer.php' script in the Quest KACE System Management Appliance 8.0.318 is accessible by
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Roundcube Webmail contains a critical PHP object deserialization vulnerability (CVE-2025-49113, CVSS 9.9) that allows au
Util/PHP/eval-stdin.php in PHPUnit before 4.8.28 and 5.x before 5.6.3 allows remote attackers to execute arbitrary PHP c
Palo Alto Networks PAN-OS management web interface contains an authentication bypass allowing unauthenticated attackers
Nagios XI version xi-5.7.5 is affected by OS command injection. Rated high severity (CVSS 8.8), this vulnerability is re
Nagios XI version xi-5.7.5 is affected by OS command injection. Rated high severity (CVSS 8.8), this vulnerability is re
The get_referers function in /opt/ws/bin/sblistpack in Sophos Web Appliance before 3.7.9.1 and 3.8 before 3.8.1.1 allows
The Backup Migration plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 1
GitHub PoC