diff --git a/remoting/protocol/session_authz_authenticator.cc b/remoting/protocol/session_authz_authenticator.cc
index 35dc027b1bb4c..070bd8ec96102 100644
--- a/remoting/protocol/session_authz_authenticator.cc
+++ b/remoting/protocol/session_authz_authenticator.cc
@@ -118,11 +118,20 @@ void SessionAuthzAuthenticator::ProcessMessage(
     case SessionAuthzState::WAITING_FOR_SESSION_TOKEN:
       VerifySessionToken(message, std::move(resume_callback));
       break;
-    case SessionAuthzState::SHARED_SECRET_FETCHED:
+    case SessionAuthzState::SHARED_SECRET_FETCHED: {
       DCHECK_EQ(underlying_->state(), WAITING_MESSAGE);
+      // |resume_callback| may synchronously destroy |this| (via
+      // JingleSession::ProcessAuthenticationStep -> Close() ->
+      // ChromotingHost::OnSessionClosed -> clients_.erase()), so guard the
+      // follow-up call with a weak pointer.
+      auto weak_this = weak_factory_.GetWeakPtr();
       underlying_->ProcessMessage(message, std::move(resume_callback));
+      if (!weak_this) {
+        return;
+      }
       StartReauthorizerIfNecessary();
       break;
+    }
     default:
       NOTREACHED() << "Unexpected SessionAuthz state: "
                    << static_cast<int>(session_authz_state_);
@@ -245,7 +254,15 @@ void SessionAuthzAuthenticator::OnVerifiedSessionToken(
                                                         WAITING_MESSAGE);
   session_policies_ = std::move(response->session_policies);
   verify_token_response_ = std::move(response);
+  // |resume_callback| may synchronously destroy |this| (via
+  // JingleSession::ProcessAuthenticationStep -> Close() ->
+  // ChromotingHost::OnSessionClosed -> clients_.erase()), so guard the
+  // follow-up call with a weak pointer.
+  auto weak_this = weak_factory_.GetWeakPtr();
   underlying_->ProcessMessage(message, std::move(resume_callback));
+  if (!weak_this) {
+    return;
+  }
   StartReauthorizerIfNecessary();
 }
 
diff --git a/remoting/protocol/session_authz_authenticator.h b/remoting/protocol/session_authz_authenticator.h
index 42b39a3442def..b0f69668aa745 100644
--- a/remoting/protocol/session_authz_authenticator.h
+++ b/remoting/protocol/session_authz_authenticator.h
@@ -11,6 +11,7 @@
 #include <string_view>
 
 #include "base/functional/callback.h"
+#include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "remoting/base/constants.h"
 #include "remoting/base/http_status.h"
@@ -148,6 +149,8 @@ class SessionAuthzAuthenticator : public Authenticator {
 
   std::string session_id_;
   std::string host_token_;
+
+  base::WeakPtrFactory<SessionAuthzAuthenticator> weak_factory_{this};
 };
 
 }  // namespace remoting::protocol