CVE-2021-21425
CVE-2021-21425 is a critical-severity vulnerability in Getgrav Grav-plugin-admin with a CVSS 3.x base score of 9.3. Its EPSS exploit-prediction score of 80% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-284.
Key facts
- Severity: Critical (CVSS 3.x base score 9.3)
- CVSS v2: 7.5
- EPSS exploit prediction: 80% (100th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-284
- Affected product: Getgrav Grav-plugin-admin
- Published:
- Last modified:
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.
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.
- How severe is CVE-2021-21425?
- CVE-2021-21425 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.
- Is CVE-2021-21425 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 80% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-21425?
- CVE-2021-21425 affects Getgrav Grav-plugin-admin. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2021-21425?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- When was CVE-2021-21425 published?
- CVE-2021-21425 was published on 2021-04-07 and last updated on 2026-06-17.
References
- http://packetstormsecurity.com/files/162283/GravCMS-1.10.7-Remote-Command-Execution.html
- http://packetstormsecurity.com/files/162457/GravCMS-1.10.7-Remote-Command-Execution.html
- https://github.com/getgrav/grav-plugin-admin/security/advisories/GHSA-6f53-6qgv-39pj
- https://pentest.blog/unexpected-journey-7-gravcms-unauthenticated-arbitrary-yaml-write-update-leads-to-code-execution/
Affected products (1)
- cpe:2.3:a:getgrav:grav-plugin-admin:*:*:*:*:*:*:*:*
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