CVE-2021-21425

Unauthenticated Arbitrary YAML Write/Update leads to Code Execution

CRITICAL
9.8
CVSS Score
Published: April 7, 2021 at 06:20 PM UTC
Updated: June 17, 2026 at 03:35 AM UTC
1 product affected across 1 vendorGrav Plugin Admin

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Severity
CRITICAL9.8
Exploit prediction
EPSS 81%

Description

Grav Admin Plugin is an HTML user interface that provides a way to configure Grav and create and modify pages. In versions 1.10.7 and earlier, an unauthenticated user can execute some methods of administrator controller without needing any credentials. Particular method execution will result in arbitrary YAML file creation or content change of existing YAML files on the system. Successfully exploitation of that vulnerability results in configuration changes, such as general site information change, custom scheduler job definition, etc. Due to the nature of the vulnerability, an adversary can change some part of the webpage, or hijack an administrator account, or execute operating system command under the context of the web-server user. This vulnerability is fixed in version 1.10.8. Blocking access to the `/admin` path from untrusted sources can be applied as a workaround.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.10.8<= 1.10.7
Affected range stops below 1.10.8, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-284NVD-CWE-Other

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