$ cve CVE-2021-21425 JSON

CVE-2021-21425 EXPLOIT

9.3

CRITICAL · CVSS 3.1 · EPSS 80.6% (pctl 100)

Patch early

A public exploit exists.

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.

Scoring

CVSS	9.3 (CRITICAL, v3.1)
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N
EPSS	80.6% — more likely to be exploited than 100% of all CVEs
Weakness	CWE-284
On CISA KEV	no
Public exploit	yes
Published	2021-04-07
Last modified	2026-06-17

Affected (1)

Vendor	Product
getgrav	grav-plugin-admin

Public exploits

Source	Title	Date
exploit-db	GravCMS 1.10.7 - Unauthenticated Arbitrary File Write (Metasploit)	2021-04-21

References

→ the Explorer · watch your stack · NVD