diff --git a/includes/OutputPage.php b/includes/OutputPage.php
index 5edf04dd14f..bcbff5cf0f8 100644
--- a/includes/OutputPage.php
+++ b/includes/OutputPage.php
@@ -3278,7 +3278,6 @@ class OutputPage extends ContextSource {
 		// Get the relevant title so that AJAX features can use the correct page name
 		// when making API requests from certain special pages (T36972).
 		$relevantTitle = $sk->getRelevantTitle();
-		$relevantUser = $sk->getRelevantUser();
 
 		if ( $ns === NS_SPECIAL ) {
 			list( $canonicalSpecialPageName, /*...*/ ) =
@@ -3379,11 +3378,9 @@ class OutputPage extends ContextSource {
 		if ( $title->isMainPage() ) {
 			$vars['wgIsMainPage'] = true;
 		}
-		if ( $relevantUser && ( !$relevantUser->isHidden() ||
-				$this->getAuthority()->isAllowed( 'hideuser' ) )
-		) {
-			// T120883 if the user is hidden and the viewer cannot see
-			// hidden users, pretend like it does not exist at all.
+
+		$relevantUser = $sk->getRelevantUser();
+		if ( $relevantUser ) {
 			$vars['wgRelevantUserName'] = $relevantUser->getName();
 		}
 		// End of stable config vars
diff --git a/includes/skins/Skin.php b/includes/skins/Skin.php
index 0e214b2b369..bc7f575ad8b 100644
--- a/includes/skins/Skin.php
+++ b/includes/skins/Skin.php
@@ -52,6 +52,10 @@ abstract class Skin extends ContextSource {
 	 */
 	protected $options = [];
 	protected $mRelevantTitle = null;
+
+	/**
+	 * @var User|null
+	 */
 	protected $mRelevantUser = null;
 
 	/**
@@ -415,7 +419,7 @@ abstract class Skin extends ContextSource {
 	 * @see self::getRelevantUser()
 	 * @param User $u
 	 */
-	public function setRelevantUser( $u ) {
+	public function setRelevantUser( User $u ) {
 		$this->mRelevantUser = $u;
 	}
 
@@ -425,31 +429,40 @@ abstract class Skin extends ContextSource {
 	 * Special:Contributions mark the user which they are relevant to so that
 	 * things like the toolbox can display the information they usually are only
 	 * able to display on a user's userpage and talkpage.
-	 * @return User
+	 *
+	 * @return User|null Null if there's no relevant user or the viewer cannot view it.
 	 */
 	public function getRelevantUser() {
-		if ( isset( $this->mRelevantUser ) ) {
-			return $this->mRelevantUser;
-		}
-		$title = $this->getRelevantTitle();
-		if ( $title->hasSubjectNamespace( NS_USER ) ) {
-			$rootUser = $title->getRootText();
-			if ( User::isIP( $rootUser ) ) {
-				$this->mRelevantUser = User::newFromName( $rootUser, false );
-			} else {
-				$user = User::newFromName( $rootUser, false );
+		if ( $this->mRelevantUser === null ) {
+			$title = $this->getRelevantTitle();
+			if ( $title->hasSubjectNamespace( NS_USER ) ) {
+				$rootUser = $title->getRootText();
+				if ( User::isIP( $rootUser ) ) {
+					$this->mRelevantUser = User::newFromName( $rootUser, false );
+				} else {
+					$user = User::newFromName( $rootUser, false );
 
-				if ( $user ) {
-					$user->load( User::READ_NORMAL );
-
-					if ( $user->isRegistered() ) {
-						$this->mRelevantUser = $user;
+					if ( $user ) {
+						$user->load( User::READ_NORMAL );
+						$this->mRelevantUser = $user->isRegistered() ? $user : null;
 					}
 				}
 			}
-			return $this->mRelevantUser;
 		}
-		return null;
+
+		$pm = MediaWikiServices::getInstance()->getPermissionManager();
+		// The relevant user should only be set if it exists. However, if it exists but is hidden,
+		// and the viewer cannot see hidden users, this exposes the fact that the user exists;
+		// pretend like the user does not exist in such cases, by setting it to null. T120883
+		if ( $this->mRelevantUser
+			&& $this->mRelevantUser->isRegistered()
+			&& $this->mRelevantUser->isHidden()
+			&& !$pm->userHasRight( $this->getUser(), 'hideuser' )
+		) {
+			return null;
+		}
+
+		return $this->mRelevantUser;
 	}
 
 	/**
diff --git a/includes/specials/SpecialListFiles.php b/includes/specials/SpecialListFiles.php
index bd5d62abba4..7b7ff187d15 100644
--- a/includes/specials/SpecialListFiles.php
+++ b/includes/specials/SpecialListFiles.php
@@ -123,7 +123,9 @@ class SpecialListFiles extends IncludableSpecialPage {
 			$out->addParserOutputContent( $pager->getBodyOutput() );
 		} else {
 			$user = $pager->getRelevantUser();
-			$this->getSkin()->setRelevantUser( $user );
+			if ( $user ) {
+				$this->getSkin()->setRelevantUser( $user );
+			}
 			$pager->getForm();
 			$out->addParserOutputContent( $pager->getFullOutput() );
 		}
diff --git a/includes/specials/SpecialLog.php b/includes/specials/SpecialLog.php
index 253b9d3707a..e08b6ddfe65 100644
--- a/includes/specials/SpecialLog.php
+++ b/includes/specials/SpecialLog.php
@@ -256,7 +256,9 @@ class SpecialLog extends SpecialPage {
 		# Set relevant user
 		if ( $pager->getPerformer() ) {
 			$performerUser = User::newFromName( $pager->getPerformer(), false );
-			$this->getSkin()->setRelevantUser( $performerUser );
+			if ( $performerUser ) {
+				$this->getSkin()->setRelevantUser( $performerUser );
+			}
 		}
 
 		# Show form options