diff --git a/sys/kern/kern_ktrace.c b/sys/kern/kern_ktrace.c
--- a/sys/kern/kern_ktrace.c
+++ b/sys/kern/kern_ktrace.c
@@ -612,7 +612,14 @@
 	auio.uio_offset = 0;
 	auio.uio_segflg = UIO_SYSSPACE;
 	auio.uio_rw = UIO_WRITE;
-	aiov[0].iov_base = (caddr_t)kth;
+	/*
+	 * ktr_buf holds a kernel address; emit a sanitized copy of the
+	 * header to the trace file so the ktr_buf field does not leak it.
+	 */
+	struct ktr_header kth_disk;
+	kth_disk = *kth;
+	kth_disk.ktr_buf = NULL;
+	aiov[0].iov_base = (caddr_t)&kth_disk;
 	aiov[0].iov_len = sizeof(struct ktr_header);
 	auio.uio_resid = sizeof(struct ktr_header);
 	auio.uio_iovcnt = 1;