CVE-2026-100669: Improper Handling of Case Sensitivity in getgrav grav
Grav before 2.0.25 ships web server configuration samples whose access-control deny rules are matched case-sensitively. In webserver-configs/web.config (IIS), every deny rule (user_sensitive_folders, user_accounts, user_data, user_error_redirect, user_pages, system, vendor, ignore_folders) sets ignoreCase="false" on its URL Rewrite <match> element, overriding the IIS default of ignoreCase="true"; because these are rewrite matches rather than <requestFiltering> elements, there is no case-insensitive fallback. On IIS running over case-insensitive NTFS, an unauthenticated remote attacker can vary the case of a folder name or file extension (for example GET /user/CONFIG/system.YAML) so that no deny rule matches and the IIS static file handler resolves and returns the underlying file, disclosing sensitive data such as configuration secrets or account password hashes. Whether a bypassed file is actually returned depends on MIME registration: .json is served by default, while .yaml/.yml return HTTP 404.3 on a stock IIS unless a YAML MIME mapping has been added. The same class of gap exists in the bundled webserver-configs/lighttpd.conf, whose user/(config|env), directory, script-extension, root-file and dotfile rules lack the (?i) modifier, though it is lower risk because lighttpd typically runs on case-sensitive filesystems. Deployments served by Apache (.htaccess), nginx, Caddy, or the PHP built-in server are not affected. The issue is fixed in 2.0.25; because the .htaccess installer heal does not touch web.config or lighttpd.conf, operators must re-copy the corrected sample files after upgrading.
AI Analysis
Technical Summary
Grav before version 2.0.25 ships with IIS web server configuration samples where URL Rewrite deny rules are matched case-sensitively (ignoreCase="false"), overriding IIS's default case-insensitive behavior. This allows unauthenticated remote attackers to bypass access restrictions by varying the case of folder names or file extensions, causing IIS to serve sensitive files such as configuration files or password hashes. The issue also exists in the bundled lighttpd configuration but is lower risk due to case-sensitive filesystems typically used. The vulnerability is resolved in Grav 2.0.25; however, operators must manually update the affected configuration files after upgrading.
Potential Impact
An unauthenticated remote attacker can bypass access-control deny rules on IIS servers hosting vulnerable Grav versions by manipulating the case of URLs, leading to unauthorized disclosure of sensitive files including configuration secrets and password hashes. The risk is mitigated on other web servers and depends on MIME type registration for file exposure. This vulnerability has a high severity with a CVSS 4.0 score of 8.7.
Mitigation Recommendations
Upgrade Grav to version 2.0.25 or later. After upgrading, manually replace the web.config and lighttpd.conf configuration files with the corrected versions provided, as the installer does not update these files automatically. Deployments using Apache, nginx, Caddy, or PHP built-in server are not affected and require no action for this issue.
CVE-2026-100669: Improper Handling of Case Sensitivity in getgrav grav
Description
Grav before 2.0.25 ships web server configuration samples whose access-control deny rules are matched case-sensitively. In webserver-configs/web.config (IIS), every deny rule (user_sensitive_folders, user_accounts, user_data, user_error_redirect, user_pages, system, vendor, ignore_folders) sets ignoreCase="false" on its URL Rewrite <match> element, overriding the IIS default of ignoreCase="true"; because these are rewrite matches rather than <requestFiltering> elements, there is no case-insensitive fallback. On IIS running over case-insensitive NTFS, an unauthenticated remote attacker can vary the case of a folder name or file extension (for example GET /user/CONFIG/system.YAML) so that no deny rule matches and the IIS static file handler resolves and returns the underlying file, disclosing sensitive data such as configuration secrets or account password hashes. Whether a bypassed file is actually returned depends on MIME registration: .json is served by default, while .yaml/.yml return HTTP 404.3 on a stock IIS unless a YAML MIME mapping has been added. The same class of gap exists in the bundled webserver-configs/lighttpd.conf, whose user/(config|env), directory, script-extension, root-file and dotfile rules lack the (?i) modifier, though it is lower risk because lighttpd typically runs on case-sensitive filesystems. Deployments served by Apache (.htaccess), nginx, Caddy, or the PHP built-in server are not affected. The issue is fixed in 2.0.25; because the .htaccess installer heal does not touch web.config or lighttpd.conf, operators must re-copy the corrected sample files after upgrading.
CVSS v4.0
Score 8.7high
Affected software
getgrav
grav
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Grav before version 2.0.25 ships with IIS web server configuration samples where URL Rewrite deny rules are matched case-sensitively (ignoreCase="false"), overriding IIS's default case-insensitive behavior. This allows unauthenticated remote attackers to bypass access restrictions by varying the case of folder names or file extensions, causing IIS to serve sensitive files such as configuration files or password hashes. The issue also exists in the bundled lighttpd configuration but is lower risk due to case-sensitive filesystems typically used. The vulnerability is resolved in Grav 2.0.25; however, operators must manually update the affected configuration files after upgrading.
Potential Impact
An unauthenticated remote attacker can bypass access-control deny rules on IIS servers hosting vulnerable Grav versions by manipulating the case of URLs, leading to unauthorized disclosure of sensitive files including configuration secrets and password hashes. The risk is mitigated on other web servers and depends on MIME type registration for file exposure. This vulnerability has a high severity with a CVSS 4.0 score of 8.7.
Mitigation Recommendations
Upgrade Grav to version 2.0.25 or later. After upgrading, manually replace the web.config and lighttpd.conf configuration files with the corrected versions provided, as the installer does not update these files automatically. Deployments using Apache, nginx, Caddy, or PHP built-in server are not affected and require no action for this issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-09-26T02:34:55.635Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ab7c9a9f7a7c5410652fd40
Added to database: 09/26/2026, 13:33:29 UTC
Last enriched: 09/26/2026, 13:49:07 UTC
Last updated: 09/27/2026, 01:57:11 UTC
Views: 12
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