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Validate user-provided regex patterns to prevent preg_match warnings #177

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Validate user-provided regex patterns to prevent preg_match warnings #177

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97a8295
Initial plan
Copilot Feb 6, 2026
f3888d1
Fix preg_match compilation error by suppressing invalid regex warnings
Copilot Feb 6, 2026
c95b8b7
Apply error suppression to all user-provided regex patterns
Copilot Feb 6, 2026
80c0af3
Replace error suppression with proper regex validation per WP standards
Copilot Feb 6, 2026
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21 changes: 16 additions & 5 deletions includes/dropins/page-cache.php
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Original file line number Diff line number Diff line change
Expand Up @@ -62,10 +62,15 @@
// Don't cache page with these user agents
if ( isset( $powered_cache_rejected_user_agents ) && ! empty( $powered_cache_rejected_user_agents ) ) {
$rejected_user_agents = implode( '|', $powered_cache_rejected_user_agents );
if ( ! empty( $rejected_user_agents ) && isset( $_SERVER['HTTP_USER_AGENT'] ) && preg_match( '#(' . $rejected_user_agents . ')#', $_SERVER['HTTP_USER_AGENT'] ) ) {
powered_cache_add_cache_miss_header( "Rejected user agent" );
if ( ! empty( $rejected_user_agents ) && isset( $_SERVER['HTTP_USER_AGENT'] ) ) {
// Validate regex pattern before using it
$pattern = '#(' . $rejected_user_agents . ')#';
@preg_match( $pattern, '' );
if ( PREG_NO_ERROR === preg_last_error() && preg_match( $pattern, $_SERVER['HTTP_USER_AGENT'] ) ) {
powered_cache_add_cache_miss_header( "Rejected user agent" );

return;
return;
}
}
}

Expand Down Expand Up @@ -150,7 +155,10 @@
if ( ! empty( $powered_cache_rejected_cookies ) ) {
$rejected_cookies = array_diff( $powered_cache_rejected_cookies, $wp_cookies, $comment_cookies, ['powered_cache_commented_posts'] );
$rejected_cookies = implode( '|', $rejected_cookies );
if ( preg_match( '#(' . $rejected_cookies . ')#', var_export( $_COOKIE, true ) ) ) {
// Validate regex pattern before using it
$pattern = '#(' . $rejected_cookies . ')#';
@preg_match( $pattern, '' );
if ( PREG_NO_ERROR === preg_last_error() && preg_match( $pattern, var_export( $_COOKIE, true ) ) ) {
powered_cache_add_cache_miss_header( "Rejected cookie" );
return;
}
Expand All @@ -173,7 +181,10 @@
continue;
}

if ( preg_match( '#^(' . $exception . ')$#', $_SERVER['REQUEST_URI'] ) ) {
// Validate regex pattern before using it
$pattern = '#^(' . $exception . ')$#';
@preg_match( $pattern, '' );
if ( PREG_NO_ERROR === preg_last_error() && preg_match( $pattern, $_SERVER['REQUEST_URI'] ) ) {
powered_cache_add_cache_miss_header( "Rejected page" );

return;
Expand Down