GHSA-m8vh-v6r6-w7p6

Suggest an improvement
Source
https://github.com/advisories/GHSA-m8vh-v6r6-w7p6
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/12/GHSA-m8vh-v6r6-w7p6/GHSA-m8vh-v6r6-w7p6.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-m8vh-v6r6-w7p6
Aliases
Published
2025-12-02T00:46:05Z
Modified
2026-09-10T03:50:58Z
Severity
  • 8.2 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H CVSS Calculator
Summary
Grav vulnerable to Denial of Service via Improper Input Handling in 'Supported' Parameter
Details

Endpoint: admin/config/system
Submenu: Languages
Parameter: Supported
Application: Grav v 1.7.48

Summary

A Denial of Service (DoS) vulnerability was identified in the "Languages" submenu of the Grav admin configuration panel (/admin/config/system). Specifically, the Supported parameter fails to properly validate user input. If a malformed value is inserted—such as a single forward slash (/) or an XSS test string—it causes a fatal regular expression parsing error on the server.

This leads to application-wide failure due to the use of the preg_match() function with an improperly constructed regular expression, resulting in the following error:

preg_match(): Unknown modifier 'o' File: /system/src/Grav/Common/Language/Language.php line 244

Once triggered, the site becomes completely unavailable to all users.

Details

  • Vulnerable Endpoint: POST /admin/config/system

  • Submenu: Languages

  • Parameter: Supported

The application dynamically constructs a regular expression using the contents of the Supported field without escaping the input using preg_quote() or proper validation. This allows attackers to inject invalid syntax into the regex engine, crashing the application during language resolution.

Stack trace excerpt:

Whoops \ Exception \ ErrorException (E_WARNING) preg_match(): Unknown modifier 'o' /system/src/Grav/Common/Language/Language.php244

Proof of Concept (PoC)

Payloads:

/

Steps to Reproduce:

  1. Log into the Grav Admin Panel.

  2. Navigate to: Configuration → System → Languages.

  3. Locate the Supported field.

  4. Insert one of the payloads above (e.g., a single slash /).

  5. Click Save.

Pasted image 20250719183223
  1. Observe: All pages in the application begin throwing a fatal error and become inaccessible.
Pasted image 20250719175229

Impact

  • Application-wide Denial of Service (DoS)

  • All login and admin views crash with the same error

  • Potentially exploitable by:

    • Admin panel users

    • CSRF if misconfigured

References

  • CWE-1333: Improper Regular Expression

  • CWE-20: Improper Input Validation

Discoverer

Marcelo Queiroz

by CVE-Hunters

Database specific 
{
    "cwe_ids":  [
        "CWE-248"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2025-12-02T00:46:05Z",
    "nvd_published_at":  "2025-12-01T22:15:50Z",
    "severity":  "HIGH"
}
References

Affected packages

Packagist / getgrav/grav

Package

Name
getgrav/grav
Purl
pkg:composer/getgrav/grav

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
1.8.0-beta.27

Affected versions

0.*
0.8.0
0.9.0
0.9.1
0.9.2
0.9.3
0.9.4
0.9.5
0.9.6
0.9.7
0.9.8
0.9.9
0.9.10
0.9.11
0.9.12
0.9.13
0.9.14
0.9.15
0.9.16
0.9.17
0.9.18
0.9.19
0.9.20
0.9.21
0.9.22
0.9.23
0.9.24
0.9.25
0.9.26
0.9.27
0.9.28
0.9.29
0.9.30
0.9.31
0.9.32
0.9.33
0.9.34
0.9.35
0.9.36
0.9.37
0.9.38
0.9.39
0.9.40
0.9.41
0.9.42
0.9.43
0.9.44
0.9.45
1.*
1.0.0-rc.1
1.0.0-rc.2
1.0.0-rc.3
1.0.0-rc.4
1.0.0-rc.5
1.0.0-rc.6
1.0.0
1.0.1
1.0.2
1.0.3
1.0.4
1.0.5
1.0.6
1.0.7
1.0.8
1.0.9
1.0.10
1.1.0-beta.1
1.1.0-beta.2
1.1.0-beta.3
1.1.0-beta.4
1.1.0-beta.5
1.1.0-rc.1
1.1.0-rc.2
1.1.0-rc.3
1.1.0
1.1.1
1.1.2
1.1.3
1.1.4
1.1.5
1.1.6
1.1.7
1.1.8
1.1.9-rc.1
1.1.9-rc.2
1.1.9-rc.3
1.1.9
1.1.10
1.1.11
1.1.12
1.1.13
1.1.14
1.1.15
1.1.16
1.1.17
1.2.0-rc.1
1.2.0-rc.2
1.2.0-rc.3
1.2.0
1.2.1
1.2.2
1.2.3
1.2.4
1.3.0-rc.1
1.3.0-rc.2
1.3.0-rc.3
1.3.0-rc.4
1.3.0-rc.5
1.3.0
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.3.6
1.3.7
1.3.8
1.3.9
1.3.10
1.4.0-beta.1
1.4.0-beta.2
1.4.0-beta.3
1.4.0-rc.1
1.4.0-rc.2
1.4.0
1.4.1
1.4.2
1.4.3
1.4.4
1.4.5
1.4.6
1.4.7
1.4.8
1.5.0-beta.1
1.5.0-beta.2
1.5.0-rc.1
1.5.0
1.5.1
1.5.2
1.5.3
1.5.4
1.5.5
1.5.6
1.5.7
1.5.8
1.5.9
1.5.10
1.6.0-beta.1
1.6.0-beta.2
1.6.0-beta.3
1.6.0-beta.4
1.6.0-beta.5
1.6.0-beta.6
1.6.0-beta.7
1.6.0-beta.8
1.6.0-rc.1
1.6.0-rc.2
1.6.0-rc.3
1.6.0-rc.4
1.6.0
1.6.1
1.6.2
1.6.3
1.6.4
1.6.5
1.6.6
1.6.7
1.6.8
1.6.9
1.6.10
1.6.11
1.6.12
1.6.13
1.6.14
1.6.15
1.6.16
1.6.17
1.6.18
1.6.19
1.6.20
1.6.21
1.6.22
1.6.23
1.6.24
1.6.25
1.6.26
1.6.27
1.6.28
1.6.29
1.6.30
1.6.31
1.7.0-beta.1
1.7.0-beta.2
1.7.0-beta.3
1.7.0-beta.4
1.7.0-beta.5
1.7.0-beta.6
1.7.0-beta.7
1.7.0-beta.8
1.7.0-beta.9
1.7.0-beta.10
1.7.0-rc.1
1.7.0-rc.2
1.7.0-rc.3
1.7.0-rc.4
1.7.0-rc.5
1.7.0-rc.6
1.7.0-rc.7
1.7.0-rc.8
1.7.0-rc.9
1.7.0-rc.10
1.7.0-rc.11
1.7.0-rc.12
1.7.0-rc.13
1.7.0-rc.14
1.7.0-rc.15
1.7.0-rc.16
1.7.0-rc.17
1.7.0-rc.18
1.7.0-rc.19
1.7.0-rc.20
1.7.0
1.7.1
1.7.3
1.7.4
1.7.5
1.7.6
1.7.7
1.7.8
1.7.9
1.7.10
1.7.12
1.7.13
1.7.14
1.7.15
1.7.16
1.7.17
1.7.18
1.7.19
1.7.20
1.7.21
1.7.22
1.7.23
1.7.24
1.7.25
1.7.26
1.7.26.1
1.7.27
1.7.27.1
1.7.28
1.7.29
1.7.29.1
1.7.30
1.7.31
1.7.32
1.7.33
1.7.34
1.7.35
1.7.36
1.7.37
1.7.37.1
1.7.38
1.7.39
1.7.39.1
1.7.39.2
1.7.39.3
1.7.39.4
1.7.40
1.7.41
1.7.41.1
1.7.41.2
1.7.42
1.7.42.1
1.7.42.2
1.7.42.3
1.7.43
1.7.44
1.7.45
1.7.46
1.7.47
1.7.48
1.7.49
1.7.49.1
1.7.49.2
1.7.49.3
1.7.49.4
1.7.49.5
1.7.51
1.7.52
1.7.53
1.7.53.1
1.7.53.2
1.7.53.3
1.8.0-beta.1
1.8.0-beta.2
1.8.0-beta.3
1.8.0-beta.4
1.8.0-beta.5
1.8.0-beta.6
1.8.0-beta.7
1.8.0-beta.8
1.8.0-beta.9
1.8.0-beta.10
1.8.0-beta.11
1.8.0-beta.12
1.8.0-beta.13
1.8.0-beta.14
1.8.0-beta.15
1.8.0-beta.16
1.8.0-beta.17
1.8.0-beta.18
1.8.0-beta.19
1.8.0-beta.20
1.8.0-beta.21
1.8.0-beta.22
1.8.0-beta.23
1.8.0-beta.24
1.8.0-beta.25
1.8.0-beta.26

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/12/GHSA-m8vh-v6r6-w7p6/GHSA-m8vh-v6r6-w7p6.json"