diff --git a/src/coredump/coredump-context.c b/src/coredump/coredump-context.c
index 24d273499a..f7e978bbfc 100644
--- a/src/coredump/coredump-context.c
+++ b/src/coredump/coredump-context.c
@@ -48,6 +48,7 @@ void coredump_context_done(CoredumpContext *context) {
         assert(context);
 
         pidref_done(&context->pidref);
+        pidref_done(&context->tidref);
         free(context->hostname);
         free(context->comm);
         free(context->exe);
@@ -266,8 +267,8 @@ int coredump_context_build_iovw(CoredumpContext *context) {
         if (r < 0)
                 return log_error_errno(r, "Failed to add COREDUMP_COMM= field: %m");
 
-        if (context->tid > 0)
-                (void) iovw_put_string_fieldf(&context->iovw, "COREDUMP_TID=", PID_FMT, context->tid);
+        if (pidref_is_set(&context->tidref))
+                (void) iovw_put_string_fieldf(&context->iovw, "COREDUMP_TID=", PID_FMT, context->tidref.pid);
 
         if (context->thread_name)
                 (void) iovw_put_string_field(&context->iovw, "COREDUMP_THREAD_NAME=", context->thread_name);
@@ -383,10 +384,10 @@ static int coredump_context_parse_from_procfs(CoredumpContext *context) {
         if (r < 0)
                 return log_error_errno(r, "Failed to get COMM: %m");
 
-        if (context->tid > 0) {
-                r = pid_get_comm(context->tid, &context->thread_name);
+        if (pidref_is_set(&context->tidref)) {
+                r = pidref_get_comm(&context->tidref, &context->thread_name);
                 if (r < 0)
-                        log_warning_errno(r, "Failed to get comm for thread "PID_FMT", ignoring: %m", context->tid);
+                        log_warning_errno(r, "Failed to get comm for thread "PID_FMT", ignoring: %m", context->tidref.pid);
         }
 
         r = get_process_exe(pid, &context->exe);
@@ -518,7 +519,7 @@ static int context_parse_one(CoredumpContext *context, MetadataField meta, bool
                 return 0;
         }
         case META_ARGV_TID:
-                r = parse_pid(s, &context->tid);
+                r = pidref_set_pidstr_full(&context->tidref, s, PIDFD_THREAD);
                 if (r < 0)
                         log_warning_errno(r, "Failed to parse TID \"%s\", ignoring: %m", s);
                 return 0;
diff --git a/src/coredump/coredump-context.h b/src/coredump/coredump-context.h
index a2ce16b853..ee4334dce2 100644
--- a/src/coredump/coredump-context.h
+++ b/src/coredump/coredump-context.h
@@ -57,7 +57,7 @@ struct CoredumpContext {
         uint64_t rlimit;   /* META_ARGV_RLIMIT */
         char *hostname;    /* META_ARGV_HOSTNAME */
         unsigned dumpable; /* META_ARGV_DUMPABLE */
-        pid_t tid;         /* META_ARGV_TID */
+        PidRef tidref;     /* META_ARGV_TID */
         char *comm;        /* META_COMM */
         char *exe;         /* META_EXE */
         char *unit;        /* META_UNIT */
@@ -78,6 +78,7 @@ struct CoredumpContext {
                 .pidref = PIDREF_NULL,          \
                 .uid = UID_INVALID,             \
                 .gid = GID_INVALID,             \
+                .tidref = PIDREF_NULL,          \
                 .mount_tree_fd = -EBADF,        \
                 .input_fd = -EBADF,             \
         }
diff --git a/src/coredump/coredump-send.c b/src/coredump/coredump-send.c
index 4817d82611..5b77301206 100644
--- a/src/coredump/coredump-send.c
+++ b/src/coredump/coredump-send.c
@@ -301,6 +301,16 @@ int coredump_send_to_container(CoredumpContext *context) {
                 context->uid = ucred.uid;
                 context->gid = ucred.gid;
 
+                /* Do not leak the TID in the initial PID namespace. */
+                int tidfd = TAKE_FD(context->tidref.fd);
+                pid_t tid = context->tidref.pid;
+                context->tidref = PIDREF_NULL;
+                if (tidfd >= 0) {
+                        r = pidref_set_pidfd_consume(&context->tidref, tidfd);
+                        if (r < 0)
+                                log_warning_errno(r, "Failed to acquire PidRef of TID ["PID_FMT"], ignoring: %m", tid);
+                }
+
                 r = coredump_context_build_iovw(context);
                 if (r < 0)
                         _exit(EXIT_FAILURE);
diff --git a/src/coredump/coredump-submit.c b/src/coredump/coredump-submit.c
index fe1042ce4a..55f8b6e9e1 100644
--- a/src/coredump/coredump-submit.c
+++ b/src/coredump/coredump-submit.c
@@ -201,8 +201,8 @@ static int fix_xattr(int fd, const CoredumpContext *context) {
         RET_GATHER(r, fix_xattr_one(fd, "user.coredump.hostname", context->hostname));
         RET_GATHER(r, fix_xattr_one(fd, "user.coredump.comm", context->comm));
         RET_GATHER(r, fix_xattr_one(fd, "user.coredump.exe", context->exe));
-        if (context->tid > 0) {
-                RET_GATHER(r, fix_xattr_format(fd, "user.coredump.tid", PID_FMT, context->tid));
+        if (pidref_is_set(&context->tidref)) {
+                RET_GATHER(r, fix_xattr_format(fd, "user.coredump.tid", PID_FMT, context->tidref.pid));
                 RET_GATHER(r, fix_xattr_one(fd, "user.coredump.thread_name", context->thread_name));
         }