CVE-2021-21425: getgrav grav-plugin-admin Improper Access Control
Vulnerability summary
CVE-2021-21425 is a critical (CVSS 9.8) Improper Access Control vulnerability in getgrav grav-plugin-admin. EPSS estimates a 80.60% chance of exploitation in the next 30 days, higher than 99.6% of scored vulnerabilities. 3 public exploits are recorded.
Timeline
- 07-04-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 2 sources · 2 versions- CVE.orgCNA9.3CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:NDiffers
EPSS trend
Probability
80.60%
Chance of exploitation in the next 30 days
Percentile
100%
Versus all other CVEs
30-day change
0.00 pp
From 80.60% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
3 foundExploit Reference (pentest.blog)
Maturity: unknown
GravCMS 1.10.7 - Unauthenticated Arbitrary File Write (Metasploit)
Maturity: poc
GravCMS Remote Command Execution
exploit/linux/http/gravcms_exec
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Getgrav1 product
- grav-plugin-admin≤ 1.10.7 | < 1.10.8
1 vendor · 1 product
References
4 links- pentest.blog/unexpected-journey-7-gravcms-unauthenticated-arbitrary-yaml-write-update-leads-to-code-executionX Refsource MISCExploitThird Party Advisory
- github.com/getgrav/grav-plugin-admin/security/advisories/GHSA-6f53-6qgv-39pjX Refsource CONFIRMThird Party Advisory
- packetstormsecurity.com/files/162283/GravCMS-1.10.7-Remote-Command-Execution.htmlX Refsource MISCThird Party AdvisoryVDB Entry
- packetstormsecurity.com/files/162457/GravCMS-1.10.7-Remote-Command-Execution.htmlX Refsource MISCThird Party AdvisoryVDB Entry