diff --git a/slang-getkey-memmove.patch b/slang-getkey-memmove.patch
new file mode 100644
index 0000000..5466f9c
--- /dev/null
+++ b/slang-getkey-memmove.patch
@@ -0,0 +1,31 @@
+commit d338fd6e949ef62e7eac4eb5c024059e02158b06
+Author: Miroslav Lichvar <mlichvar@redhat.com>
+Date:   Wed Jul 25 13:07:42 2018 +0200
+
+    Replaced memcpy in SLang_getkey
+    
+    memcpy() is not defined for overlapping buffers, i.e. it may copy bytes
+    in any direction. As SLMEMMOVE is not defined in slang, replace the
+    SLMEMCPY call with a for loop.
+
+diff --git a/src/slgetkey.c b/src/slgetkey.c
+index 86e7946..d9bc678 100644
+--- a/src/slgetkey.c
++++ b/src/slgetkey.c
+@@ -40,13 +40,13 @@ unsigned int SLang_getkey (void)
+ 
+    if (SLang_Input_Buffer_Len)
+      {
+-	unsigned int imax;
++	unsigned int i, imax;
+ 	ch = (unsigned int) *SLang_Input_Buffer;
+ 	SLang_Input_Buffer_Len--;
+ 	imax = SLang_Input_Buffer_Len;
+ 
+-	SLMEMCPY ((char *) SLang_Input_Buffer,
+-		(char *) (SLang_Input_Buffer + 1), imax);
++	for (i = 0; i < imax; i++)
++	  SLang_Input_Buffer[i] = SLang_Input_Buffer[i + 1];
+      }
+    else if (SLANG_GETKEY_ERROR == (ch = _pSLsys_getkey ())) return ch;
+ 
diff --git a/slang.spec b/slang.spec
index e30034c..ea5a307 100644
--- a/slang.spec
+++ b/slang.spec
@@ -11,6 +11,8 @@ Release:	3%{?dist}
 License:	GPLv2+
 URL:		https://www.jedsoft.org/slang/
 Source:		https://www.jedsoft.org/releases/%{name}/%{name}-%{version}.tar.bz2
+# don't use memcpy() on overlapping buffers
+Patch1:		slang-getkey-memmove.patch
 # disable test that fails with SIGHUP ignored (e.g. in koji)
 Patch2:		slang-sighuptest.patch
 BuildRequires:	gcc libpng-devel pcre-devel zlib-devel
@@ -52,6 +54,7 @@ based on the S-Lang extension language.
 
 %prep
 %setup -q
+%patch1 -p1 -b .getkey-memmove
 %patch2 -p1 -b .sighuptest
 
 # fix permissions of installed modules