Apply by doing:
	cd /usr/src
	patch -p0 < 007_cd9660.patch

And then rebuild your kernel.

Index: sys/isofs/cd9660/cd9660_extern.h
===================================================================
RCS file: /cvs/src/sys/isofs/cd9660/cd9660_extern.h,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- sys/isofs/cd9660/cd9660_extern.h	2000/02/07 04:57:15	1.4
+++ sys/isofs/cd9660/cd9660_extern.h	2000/06/07 23:25:08	1.5
@@ -84,8 +84,8 @@
 #define lblkno(imp, loc)	((loc) >> (imp)->im_bshift)
 #define blksize(imp, ip, lbn)	((imp)->logical_block_size)
 
-int cd9660_mount __P((struct mount *,
-	    const char *, caddr_t, struct nameidata *, struct proc *));
+int cd9660_mount __P((struct mount *, const char *, caddr_t,
+                      struct nameidata *, struct proc *));
 int cd9660_start __P((struct mount *, int, struct proc *));
 int cd9660_unmount __P((struct mount *, int, struct proc *));
 int cd9660_root __P((struct mount *, struct vnode **));
@@ -96,6 +96,8 @@
 int cd9660_fhtovp __P((struct mount *, struct fid *, struct vnode **));
 int cd9660_vptofh __P((struct vnode *, struct fid *));
 int cd9660_init __P((struct vfsconf *));
+int cd9660_check_export __P((struct mount *, struct mbuf *, int *,
+                             struct ucred **));
 #define cd9660_sysctl ((int (*) __P((int *, u_int, void *, size_t *, void *, \
                                     size_t, struct proc *)))eopnotsupp)
 
Index: sys/isofs/cd9660/cd9660_vfsops.c
===================================================================
RCS file: /cvs/src/sys/isofs/cd9660/cd9660_vfsops.c,v
retrieving revision 1.19
retrieving revision 1.20
diff -u -r1.19 -r1.20
--- sys/isofs/cd9660/cd9660_vfsops.c	2000/02/07 04:57:15	1.19
+++ sys/isofs/cd9660/cd9660_vfsops.c	2000/06/07 23:25:08	1.20
@@ -77,7 +77,8 @@
 	cd9660_fhtovp,
 	cd9660_vptofh,
 	cd9660_init,
-	cd9660_sysctl
+	cd9660_sysctl,
+	cd9660_check_export
 };
 
 /*
@@ -962,5 +963,31 @@
 	printf("vptofh: ino %d, start %ld\n",
 	    ifhp->ifid_ino,ifhp->ifid_start);
 #endif
+	return (0);
+}
+
+/*
+ * Verify a remote client has export rights and return these rights via
+ * exflagsp and credanonp.
+ */
+int
+cd9660_check_export(mp, nam, exflagsp, credanonp)
+	register struct mount *mp;
+	struct mbuf *nam;
+	int *exflagsp;
+	struct ucred **credanonp;
+{
+	register struct netcred *np;
+	register struct iso_mnt *imp = VFSTOISOFS(mp);
+
+	/*
+	 * Get the export permission structure for this <mp, client> tuple.
+	 */
+	np = vfs_export_lookup(mp, &imp->im_export, nam);
+	if (np == NULL)
+		return (EACCES);
+
+	*exflagsp = np->netc_exflags;
+	*credanonp = &np->netc_anon;
 	return (0);
 }