diff --git a/WHATS_NEW b/WHATS_NEW
index 1a4ba1094..649afe2da 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 2.02.06 -
 =================================
+  Tighten region size validation.
   Ignore empty strings in config files.
   Require non-zero regionsize and document parameter on lvcreate man page.
   Invalidate cache if composition of VG changed externally.
diff --git a/tools/lvconvert.c b/tools/lvconvert.c
index 9dc676cec..10c9f9567 100644
--- a/tools/lvconvert.c
+++ b/tools/lvconvert.c
@@ -101,6 +101,8 @@ static int _lvconvert_name_params(struct lvconvert_params *lp,
 static int _read_params(struct lvconvert_params *lp, struct cmd_context *cmd,
 			int argc, char **argv)
 {
+	int region_size;
+
 	memset(lp, 0, sizeof(*lp));
 
 	if (arg_count(cmd, mirrors_ARG) + arg_count(cmd, snapshot_ARG) != 1) {
@@ -165,6 +167,7 @@ static int _read_params(struct lvconvert_params *lp, struct cmd_context *cmd,
 	 	 * --regionsize is only valid if converting an LV into a mirror.
 	 	 * Checked when we know the state of the LV being converted.
 	 	 */
+
 		if (arg_count(cmd, regionsize_ARG)) {
 			if (arg_sign_value(cmd, regionsize_ARG, 0) ==
 				    SIGN_MINUS) {
@@ -173,11 +176,18 @@ static int _read_params(struct lvconvert_params *lp, struct cmd_context *cmd,
 			}
 			lp->region_size = 2 * arg_uint_value(cmd,
 							     regionsize_ARG, 0);
-		} else
-			lp->region_size = 2 * find_config_int(cmd->cft->root,
+		} else {
+			region_size = 2 * find_config_int(cmd->cft->root,
 						"activation/mirror_region_size",
 						DEFAULT_MIRROR_REGION_SIZE);
-	
+			if (region_size < 0) {
+				log_error("Negative regionsize in "
+					  "configuration file is invalid");
+				return 0;
+			}
+			lp->region_size = region_size;
+		}
+
 		if (lp->region_size & (lp->region_size - 1)) {
 			log_error("Region size (%" PRIu32
 				  ") must be a power of 2", lp->region_size);
diff --git a/tools/lvcreate.c b/tools/lvcreate.c
index dc26216f7..414987241 100644
--- a/tools/lvcreate.c
+++ b/tools/lvcreate.c
@@ -234,6 +234,7 @@ static int _read_mirror_params(struct lvcreate_params *lp,
 			       int *pargc, char ***pargv)
 {
 	int argc = *pargc;
+	int region_size;
 
 	if (argc && (unsigned) argc < lp->mirrors) {
 		log_error("Too few physical volumes on "
@@ -247,10 +248,17 @@ static int _read_mirror_params(struct lvcreate_params *lp,
 			return 0;
 		}
 		lp->region_size = 2 * arg_uint_value(cmd, regionsize_ARG, 0);
-	} else
-		lp->region_size = 2 * find_config_int(cmd->cft->root,
+	} else {
+		region_size = 2 * find_config_int(cmd->cft->root,
 					"activation/mirror_region_size",
 					DEFAULT_MIRROR_REGION_SIZE);
+		if (region_size < 0) {
+			log_error("Negative regionsize in configuration file "
+				  "is invalid");
+			return 0;
+		}
+		lp->region_size = region_size;
+	}
 
 	if (lp->region_size & (lp->region_size - 1)) {
 		log_error("Region size (%" PRIu32 ") must be a power of 2",