diff --git a/libr/asm/p/asm_cris_gnu.c b/libr/asm/p/asm_cris_gnu.c
index dfa304f515..8a64a8ae42 100644
--- a/libr/asm/p/asm_cris_gnu.c
+++ b/libr/asm/p/asm_cris_gnu.c
@@ -26,7 +26,14 @@ static RStrBuf *buf_global = NULL;
 static unsigned char bytes[8];
 
 static int cris_buffer_read_memory (bfd_vma memaddr, bfd_byte *myaddr, ut32 length, struct disassemble_info *info) {
-	memcpy (myaddr, bytes, length);
+	int delta = (memaddr - Offset);
+	if (delta < 0) {
+		return -1;      // disable backward reads
+	}
+	if ((delta + length) > 8) {
+		return -1;
+	}
+	memcpy (myaddr, bytes + delta, length);
 	return 0;
 }
 
diff --git a/libr/asm/p/asm_hppa_gnu.c b/libr/asm/p/asm_hppa_gnu.c
index bda704a2f7..086020e795 100644
--- a/libr/asm/p/asm_hppa_gnu.c
+++ b/libr/asm/p/asm_hppa_gnu.c
@@ -27,7 +27,14 @@ static int hppa_buffer_read_memory (bfd_vma memaddr, bfd_byte *myaddr, ut32 leng
 		return 0;
 	}
 #endif
-	memcpy (myaddr, bytes, length);
+	int delta = (memaddr - Offset);
+	if (delta < 0) {
+		return -1;      // disable backward reads
+	}
+	if ((delta + length) > 4) {
+		return -1;
+	}
+	memcpy (myaddr, bytes + delta, length);
 	return 0;
 }
 
diff --git a/libr/asm/p/asm_lanai_gnu.c b/libr/asm/p/asm_lanai_gnu.c
index 3da59579fb..f5474ab483 100644
--- a/libr/asm/p/asm_lanai_gnu.c
+++ b/libr/asm/p/asm_lanai_gnu.c
@@ -14,7 +14,14 @@ static RStrBuf *buf_global = NULL;
 static unsigned char bytes[4];
 
 static int lanai_buffer_read_memory(bfd_vma memaddr, bfd_byte *myaddr, ut32 length, struct disassemble_info *info) {
-	memcpy (myaddr, bytes, length);
+	int delta = (memaddr - Offset);
+	if (delta < 0) {
+		return -1;      // disable backward reads
+	}
+	if ((delta + length) > 4) {
+		return -1;
+	}
+	memcpy (myaddr, bytes + delta, length);
 	return 0;
 }
 
diff --git a/libr/asm/p/asm_mips_gnu.c b/libr/asm/p/asm_mips_gnu.c
index 3aeeaf8484..c83cb44053 100644
--- a/libr/asm/p/asm_mips_gnu.c
+++ b/libr/asm/p/asm_mips_gnu.c
@@ -21,7 +21,14 @@ static char *pre_cpu = NULL;
 static char *pre_features = NULL;
 
 static int mips_buffer_read_memory(bfd_vma memaddr, bfd_byte *myaddr, unsigned int length, struct disassemble_info *info) {
-	memcpy (myaddr, bytes, length);
+	int delta = (memaddr - Offset);
+	if (delta < 0) {
+		return -1;      // disable backward reads
+	}
+	if ((delta + length) > 4) {
+		return -1;
+	}
+	memcpy (myaddr, bytes + delta, length);
 	return 0;
 }
 
diff --git a/libr/asm/p/asm_ppc_gnu.c b/libr/asm/p/asm_ppc_gnu.c
index 977b22fc20..f3724d7402 100644
--- a/libr/asm/p/asm_ppc_gnu.c
+++ b/libr/asm/p/asm_ppc_gnu.c
@@ -17,7 +17,14 @@ static RStrBuf *buf_global = NULL;
 static unsigned char bytes[4];
 
 static int ppc_buffer_read_memory (bfd_vma memaddr, bfd_byte *myaddr, ut32 length, struct disassemble_info *info) {
-	memcpy (myaddr, bytes, length);
+	int delta = (memaddr - Offset);
+	if (delta < 0) {
+		return -1;      // disable backward reads
+	}
+	if ((delta + length) > 4) {
+		return -1;
+	}
+	memcpy (myaddr, bytes + delta, length);
 	return 0;
 }
 
diff --git a/libr/asm/p/asm_sparc_gnu.c b/libr/asm/p/asm_sparc_gnu.c
index 1f1b815fe2..4539dd49a4 100644
--- a/libr/asm/p/asm_sparc_gnu.c
+++ b/libr/asm/p/asm_sparc_gnu.c
@@ -15,6 +15,13 @@ static RStrBuf *buf_global = NULL;
 static unsigned char bytes[4];
 
 static int sparc_buffer_read_memory (bfd_vma memaddr, bfd_byte *myaddr, unsigned int length, struct disassemble_info *info) {
+	int delta = (memaddr - Offset);
+	if (delta < 0) {
+		return -1;      // disable backward reads
+	}
+	if ((delta + length) > 4) {
+		return -1;
+	}
 	memcpy (myaddr, bytes, length);
 	return 0;
 }
diff --git a/libr/asm/p/asm_v850_gnu.c b/libr/asm/p/asm_v850_gnu.c
index c2f69b0254..fce594640d 100644
--- a/libr/asm/p/asm_v850_gnu.c
+++ b/libr/asm/p/asm_v850_gnu.c
@@ -16,7 +16,14 @@ static RStrBuf *buf_global = NULL;
 static ut8 bytes[8];
 
 static int v850_buffer_read_memory(bfd_vma memaddr, bfd_byte *myaddr, ut32 length, struct disassemble_info *info) {
-	memcpy (myaddr, bytes, length);
+	int delta = (memaddr - Offset);
+	if (delta < 0) {
+		return -1;      // disable backward reads
+	}
+	if ((delta + length) > 8) {
+		return -1;
+	}
+	memcpy (myaddr, bytes + delta, length);
 	return 0;
 }
 
diff --git a/test/db/anal/v850.gnu b/test/db/anal/v850.gnu
new file mode 100644
index 0000000000..ebca0e9572
--- /dev/null
+++ b/test/db/anal/v850.gnu
@@ -0,0 +1,12 @@
+NAME=v850.gnu proper imm32 handling
+FILE=malloc://1024
+CMDS=<<EOF
+e asm.arch = v850.gnu
+wx 210674060000210674061234
+pi 2 @0
+EOF
+EXPECT=<<EOF
+mov 0x674, r1
+mov 0x34120674, r1
+EOF
+RUN