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Public proof of conceptFix available

CVE-2021-21425

A public proof of concept exists; no exploitation attested.

  • Published2021-04-07
  • Fixed in1.10.8
  • WeaknessCWE-284

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-04-0719:15CVE publishedNVD
  2. 2021-04-21Exploit-DB entryExploit-DB

Observed activity

isMalicious corpus · updated 2026-11-03 15:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-21425?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-21425?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Getgrav grav-plugin-admin
BranchAffectedFixed in
1.10< 1.10.81.10.8

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Getgrav grav-plugin-admin to 1.10.8

Detection

read 2026-11-02 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
EDB-49788
Exploit-DB
Proof-of-concept repositories
6 repositories, unverifiedCsEnox/CVE-2021-21425grey-master-a/GravCMS_Nmap_ScriptbluetoothStrawberry/cve-2021-21425afifudinmtop/CVE-2021-21425d4ytox/CVE-2021-21425
PoC-in-GitHub
Metasploit modules
1 moduleexploit/linux/http/gravcms_execrank: normalModule metadata: Metasploit Framework, © Rapid7, Inc., BSD-3-Clause.
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2021-04-07
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-21425?

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.

Is CVE-2021-21425 actively exploited?

Active exploitation of CVE-2021-21425 has not been confirmed. Its EPSS score was 80.6% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-21425?

CVE-2021-21425 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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Sources for this record