diff --git a/NEWS b/NEWS
index 92ce30a42..9868bedc7 100644
--- a/NEWS
+++ b/NEWS
@@ -12,6 +12,9 @@ Any uppercase BUG_* names are modernish shell bug IDs.
   3. The -c/--call, -n/--name and -s/--standard options matched all variable
      names provided by 'getconf -a', even if none were actual matches.
 
+- The readonly attribute of ksh variables is no longer imported from
+  or exported to other ksh shell instances through the environment.
+
 2021-04-16:
 
 - Fixed a bug in emacs mode: after using tab completion to complete the name
diff --git a/src/cmd/ksh93/COMPATIBILITY b/src/cmd/ksh93/COMPATIBILITY
index 5d6f267b0..a4e1c7705 100644
--- a/src/cmd/ksh93/COMPATIBILITY
+++ b/src/cmd/ksh93/COMPATIBILITY
@@ -129,6 +129,9 @@ For more details, see the NEWS file and for complete details, see the git log.
 	To invoke a possible external command at that path, you can still use
 	a non-canonical path, e.g.: /opt//ast/bin/cat or /opt/ast/./bin/cat
 
+24.	The readonly attribute of ksh variables is no longer imported from
+	or exported to other ksh shell instances through the environment.
+
 ____________________________________________________________________________
 
 		KSH-93 VS. KSH-88
diff --git a/src/cmd/ksh93/sh/init.c b/src/cmd/ksh93/sh/init.c
index 97ca10153..852a14394 100644
--- a/src/cmd/ksh93/sh/init.c
+++ b/src/cmd/ksh93/sh/init.c
@@ -1986,6 +1986,9 @@ static void env_import_attributes(Shell_t *shp, char *next)
 					size--;
 				}
 			}
+			flag &= ~NV_RDONLY;	/* refuse to import readonly attribute */
+			if(!flag)
+				continue;
 			nv_newattr(np,flag|NV_IMPORT|NV_EXPORT,size);
 		}
 	}
diff --git a/src/cmd/ksh93/sh/name.c b/src/cmd/ksh93/sh/name.c
index b77e82ff3..9b571bd8a 100644
--- a/src/cmd/ksh93/sh/name.c
+++ b/src/cmd/ksh93/sh/name.c
@@ -2241,7 +2241,7 @@ char **sh_envgen(void)
 	/* Export variable attributes into env var named by e_envmarker, unless POSIX mode is on */
 	cp = data.attval = strcopy(*data.argnam,e_envmarker);
 	if(!sh_isoption(SH_POSIX))
-		nv_scan(shp->var_tree, attstore,&data,0,(NV_RDONLY|NV_UTOL|NV_LTOU|NV_RJUST|NV_LJUST|NV_ZFILL|NV_INTEGER));
+		nv_scan(shp->var_tree, attstore,&data,0,(NV_UTOL|NV_LTOU|NV_RJUST|NV_LJUST|NV_ZFILL|NV_INTEGER));
 	*data.attval = 0;
 	if(cp!=data.attval)
 		data.argnam++;