diff --git a/projects/packages/cookie-consent/changelog/fix-consent-logger-nonce b/projects/packages/cookie-consent/changelog/fix-consent-logger-nonce
new file mode 100644
index 000000000000..b6230661a8ac
--- /dev/null
+++ b/projects/packages/cookie-consent/changelog/fix-consent-logger-nonce
@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Consent log: send a REST nonce for logged-in visitors so the consent row records the real user ID instead of 0.
diff --git a/projects/packages/cookie-consent/src/class-cookie-consent.php b/projects/packages/cookie-consent/src/class-cookie-consent.php
index dddd9653b7e1..6315a987bec6 100644
--- a/projects/packages/cookie-consent/src/class-cookie-consent.php
+++ b/projects/packages/cookie-consent/src/class-cookie-consent.php
@@ -1105,15 +1105,26 @@ public static function enqueue_assets() {
 		// Resolve the configured Tracks event prefix once so it can be shared below.
 		$config = self::get_config();
 
+		$config_data = array(
+			'apiUrl'      => rest_url( 'jetpack/v4/cookie-consent/consent-log' ),
+			'eventPrefix' => $config['event_prefix'],
+		);
+
+		// Only expose a REST nonce to logged-in visitors, so the consent logger can
+		// authenticate and record the real user_id. Anonymous visitors deliberately get
+		// none: their pages are full-page-cached, a cached nonce would go stale and make
+		// core reject the request (rest_cookie_invalid_nonce). Without a nonce core treats
+		// the request as anonymous and stores user_id = 0, which is correct for them.
+		if ( is_user_logged_in() ) {
+			$config_data['nonce'] = wp_create_nonce( 'wp_rest' );
+		}
+
 		// Pass REST API URL and Tracks event prefix to the module via global config.
 		wp_print_inline_script_tag(
 			sprintf(
 				'window.jetpackCookieConsentConfig = %s;',
 				wp_json_encode(
-					array(
-						'apiUrl'      => rest_url( 'jetpack/v4/cookie-consent/consent-log' ),
-						'eventPrefix' => $config['event_prefix'],
-					),
+					$config_data,
 					JSON_HEX_TAG | JSON_HEX_AMP | JSON_HEX_APOS | JSON_HEX_QUOT
 				)
 			),
diff --git a/projects/packages/cookie-consent/src/modules/cookie-consent/logger.ts b/projects/packages/cookie-consent/src/modules/cookie-consent/logger.ts
index cc2bb44a796f..29165bcb87b6 100644
--- a/projects/packages/cookie-consent/src/modules/cookie-consent/logger.ts
+++ b/projects/packages/cookie-consent/src/modules/cookie-consent/logger.ts
@@ -24,12 +24,20 @@ async function logConsentEvent(
 		return;
 	}
 
+	const headers: Record< string, string > = {
+		'Content-Type': 'application/json',
+	};
+	// Send the REST nonce when present (logged-in visitors only) so the request
+	// authenticates and the consent row records the real user_id instead of 0.
+	const nonce = window.jetpackCookieConsentConfig?.nonce;
+	if ( nonce ) {
+		headers[ 'X-WP-Nonce' ] = nonce;
+	}
+
 	try {
 		const response = await fetch( apiUrl, {
 			method: 'POST',
-			headers: {
-				'Content-Type': 'application/json',
-			},
+			headers,
 			body: JSON.stringify( {
 				event_type: eventType,
 				url: window.location.href,
diff --git a/projects/packages/cookie-consent/src/modules/cookie-consent/types.ts b/projects/packages/cookie-consent/src/modules/cookie-consent/types.ts
index 6c0ae6c35898..e1f1198ac659 100644
--- a/projects/packages/cookie-consent/src/modules/cookie-consent/types.ts
+++ b/projects/packages/cookie-consent/src/modules/cookie-consent/types.ts
@@ -41,6 +41,7 @@ declare global {
 		jetpackCookieConsentConfig?: {
 			apiUrl: string;
 			eventPrefix?: string;
+			nonce?: string;
 		};
 		wp_set_consent?: ( category: string, value: 'allow' | 'deny' ) => void;
 		wp_consent_type?: ConsentType;