CVE-2026-63190
FearlessCMS: Unauthenticated debug scripts expose filesystem operations and XSS
FearlessCMS is a flat-file content management system centered on simplicity and open source. Prior to version 0.1.4, five debug/test PHP scripts under admin/ perform privileged operations without isLoggedIn() authentication checks, CSRF protection or adequate path validation. On PHP's built-in development server, including the default Docker deployment, router.php checks an unnormalized admin URI prefix while the filesystem resolves dot segments, so /./admin/ bypasses the admin login gate and executes those scripts directly. In admin/debug_save_flow.php, attacker-controlled path and content reach file_put_contents for arbitrary .md writes under content/ or outside it through path traversal, enabling site defacement and stored JavaScript in public pages; print_r($_POST) output without htmlspecialchars escaping also causes reflected cross-site scripting. The admin/debug_content.php path parameter reaches scandir(), file_get_contents() and posix_getpwuid(), permitting arbitrary directory enumeration and .md file reads that expose absolute paths, ownership, permissions, hashes and content previews. The admin/preview-handler.php endpoint accepts JSON content and title and writes enumerable files under content/_preview/, enabling stored cross-site scripting and disk exhaustion. The admin/testdebug.php endpoint appends to admin/testdebug.log without authentication, also enabling disk exhaustion. The admin/test_redirect.php script exposes a test artifact but escapes its inputs and is not itself an XSS sink. Stored script execution can steal sessions and compromise administrators when they view affected content. Reads and writes execute with PHP's privileges; the tested deployment runs PHP as root, amplifying filesystem impact. This issue is fixed in version 0.1.4.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
9.4
FearlessCMS: Unauthenticated debug scripts expose filesystem operations and XSS
FearlessCMS is a flat-file content management system centered on simplicity and open source. Prior to version 0.1.4, five debug/test PHP scripts under admin/ perform privileged operations without isLoggedIn() authentication checks, CSRF protection or adequate path validation. On PHP's built-in development server, including the default Docker deployment, router.php checks an unnormalized admin URI prefix while the filesystem resolves dot segments, so /./admin/ bypasses the admin login gate and executes those scripts directly. In admin/debug_save_flow.php, attacker-controlled path and content reach file_put_contents for arbitrary .md writes under content/ or outside it through path traversal, enabling site defacement and stored JavaScript in public pages; print_r($_POST) output without htmlspecialchars escaping also causes reflected cross-site scripting. The admin/debug_content.php path parameter reaches scandir(), file_get_contents() and posix_getpwuid(), permitting arbitrary directory enumeration and .md file reads that expose absolute paths, ownership, permissions, hashes and content previews. The admin/preview-handler.php endpoint accepts JSON content and title and writes enumerable files under content/_preview/, enabling stored cross-site scripting and disk exhaustion. The admin/testdebug.php endpoint appends to admin/testdebug.log without authentication, also enabling disk exhaustion. The admin/test_redirect.php script exposes a test artifact but escapes its inputs and is not itself an XSS sink. Stored script execution can steal sessions and compromise administrators when they view affected content. Reads and writes execute with PHP's privileges; the tested deployment runs PHP as root, amplifying filesystem impact. This issue is fixed in version 0.1.4.
- Record
CVE-2026-63190- CVSS 3.1
- 9.4 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L - Weakness
- CWE-306, CWE-288, CWE-22, CWE-79, CWE-200
- Updated
- 2026-11-02
EUVDEUVD-2026-112405
9.4
FearlessCMS is a flat-file content management system centered on simplicity and open source. Prior to version 0.1.4, five debug/test PHP scripts under admin/ perform privileged operations without isLoggedIn() authentication checks, CSRF protection or adequate path validation. On PHP's built-in development server, including the default Docker deployment, router.php checks an unnormalized admin URI prefix while the filesystem resolves dot segments, so /./admin/ bypasses the admin login gate and executes those scripts directly. In admin/debug_save_flow.php, attacker-controlled path and content reach file_put_contents for arbitrary .md writes under content/ or outside it through path traversal, enabling site defacement and stored JavaScript in public pages; print_r($_POST) output without htmlspecialchars escaping also causes reflected cross-site scripting. The admin/debug_content.php path parameter reaches scandir(), file_get_contents() and posix_getpwuid(), permitting arbitrary directory enumeration and .md file reads that expose absolute paths, ownership, permissions, hashes and content previews. The admin/preview-handler.php endpoint accepts JSON content and title and writes enumerable files under content/_preview/, enabling stored cross-site scripting and disk exhaustion. The admin/testdebug.php endpoint appends to admin/testdebug.log without authentication, also enabling disk exhaustion. The admin/test_redirect.php script exposes a test artifact but escapes its inputs and is not itself an XSS sink. Stored script execution can steal sessions and compromise administrators when they view affected content. Reads and writes execute with PHP's privileges; the tested deployment runs PHP as root, amplifying filesystem impact. This issue is fixed in version 0.1.4.
- Record
EUVD-2026-112405- CVSS 3.1
- 9.4 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L - Updated
- 2026-11-02
NVD
9.4
FearlessCMS is a flat-file content management system centered on simplicity and open source. Prior to version 0.1.4, five debug/test PHP scripts under admin/ perform privileged operations without isLoggedIn() authentication checks, CSRF protection or adequate path validation. On PHP's built-in development server, including the default Docker deployment, router.php checks an unnormalized admin URI prefix while the filesystem resolves dot segments, so /./admin/ bypasses the admin login gate and executes those scripts directly. In admin/debug_save_flow.php, attacker-controlled path and content reach file_put_contents for arbitrary .md writes under content/ or outside it through path traversal, enabling site defacement and stored JavaScript in public pages; print_r($_POST) output without htmlspecialchars escaping also causes reflected cross-site scripting. The admin/debug_content.php path parameter reaches scandir(), file_get_contents() and posix_getpwuid(), permitting arbitrary directory enumeration and .md file reads that expose absolute paths, ownership, permissions, hashes and content previews. The admin/preview-handler.php endpoint accepts JSON content and title and writes enumerable files under content/_preview/, enabling stored cross-site scripting and disk exhaustion. The admin/testdebug.php endpoint appends to admin/testdebug.log without authentication, also enabling disk exhaustion. The admin/test_redirect.php script exposes a test artifact but escapes its inputs and is not itself an XSS sink. Stored script execution can steal sessions and compromise administrators when they view affected content. Reads and writes execute with PHP's privileges; the tested deployment runs PHP as root, amplifying filesystem impact. This issue is fixed in version 0.1.4.
- Record
CVE-2026-63190- CVSS 3.1
- 9.4 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L - Weakness
- CWE-22, CWE-79, CWE-200, CWE-288, CWE-306
- Updated
- 2026-11-02
OSV
9.4
FearlessCMS: Unauthenticated debug scripts expose filesystem operations and XSS
FearlessCMS is a flat-file content management system centered on simplicity and open source. Prior to version 0.1.4, five debug/test PHP scripts under admin/ perform privileged operations without isLoggedIn() authentication checks, CSRF protection or adequate path validation. On PHP's built-in development server, including the default Docker deployment, router.php checks an unnormalized admin URI prefix while the filesystem resolves dot segments, so /./admin/ bypasses the admin login gate and executes those scripts directly. In admin/debug_save_flow.php, attacker-controlled path and content reach file_put_contents for arbitrary .md writes under content/ or outside it through path traversal, enabling site defacement and stored JavaScript in public pages; print_r($_POST) output without htmlspecialchars escaping also causes reflected cross-site scripting. The admin/debug_content.php path parameter reaches scandir(), file_get_contents() and posix_getpwuid(), permitting arbitrary directory enumeration and .md file reads that expose absolute paths, ownership, permissions, hashes and content previews. The admin/preview-handler.php endpoint accepts JSON content and title and writes enumerable files under content/_preview/, enabling stored cross-site scripting and disk exhaustion. The admin/testdebug.php endpoint appends to admin/testdebug.log without authentication, also enabling disk exhaustion. The admin/test_redirect.php script exposes a test artifact but escapes its inputs and is not itself an XSS sink. Stored script execution can steal sessions and compromise administrators when they view affected content. Reads and writes execute with PHP's privileges; the tested deployment runs PHP as root, amplifying filesystem impact. This issue is fixed in version 0.1.4.
- Record
CVE-2026-63190- CVSS 3.1
- 9.4 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L - Weakness
- CWE-200, CWE-22, CWE-288, CWE-306, CWE-79
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-63190 is a critical vulnerability (CVSS 9.4) in Fearlessgeekmedia Fearlesscms, published October 28, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.54%, the 45th percentile. No source names a fixed version.
References
github.com/fearlessgeekmedia/FearlessCMS/security/advisories/GHSA-3mq8-hrhf-7hv6
github.com/fearlessgeekmedia/FearlessCMS/commit/59fb22cf989b5ba14c387c3212e15b146e02cf9a
github.com/fearlessgeekmedia/FearlessCMS/tree/0.1.4
github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63190.json
nvd.nist.gov/vuln/detail/CVE-2026-63190