diff --git a/arch/X86/X86DisassemblerDecoder.c b/arch/X86/X86DisassemblerDecoder.c
index 0938d56130..e915fb9e24 100644
--- a/arch/X86/X86DisassemblerDecoder.c
+++ b/arch/X86/X86DisassemblerDecoder.c
@@ -523,20 +523,52 @@ static int readPrefixes(struct InternalInstruction *insn)
 		case 0x65: /* GS segment override */
 			switch (byte) {
 			case 0x2e:
-				insn->segmentOverride = SEG_OVERRIDE_CS;
-				insn->prefix1 = byte;
+				if (insn->mode != MODE_64BIT ||
+				    (insn->prefix1 != 0x64 &&
+				     insn->prefix1 != 0x65)) {
+					if (insn->mode != MODE_64BIT) {
+						insn->segmentOverride =
+							SEG_OVERRIDE_CS;
+					}
+
+					insn->prefix1 = byte;
+				}
 				break;
 			case 0x36:
-				insn->segmentOverride = SEG_OVERRIDE_SS;
-				insn->prefix1 = byte;
+				if (insn->mode != MODE_64BIT ||
+				    (insn->prefix1 != 0x64 &&
+				     insn->prefix1 != 0x65)) {
+					if (insn->mode != MODE_64BIT) {
+						insn->segmentOverride =
+							SEG_OVERRIDE_SS;
+					}
+
+					insn->prefix1 = byte;
+				}
 				break;
 			case 0x3e:
-				insn->segmentOverride = SEG_OVERRIDE_DS;
-				insn->prefix1 = byte;
+				if (insn->mode != MODE_64BIT ||
+				    (insn->prefix1 != 0x64 &&
+				     insn->prefix1 != 0x65)) {
+					if (insn->mode != MODE_64BIT) {
+						insn->segmentOverride =
+							SEG_OVERRIDE_DS;
+					}
+
+					insn->prefix1 = byte;
+				}
 				break;
 			case 0x26:
-				insn->segmentOverride = SEG_OVERRIDE_ES;
-				insn->prefix1 = byte;
+				if (insn->mode != MODE_64BIT ||
+				    (insn->prefix1 != 0x64 &&
+				     insn->prefix1 != 0x65)) {
+					if (insn->mode != MODE_64BIT) {
+						insn->segmentOverride =
+							SEG_OVERRIDE_ES;
+					}
+
+					insn->prefix1 = byte;
+				}
 				break;
 			case 0x64:
 				insn->segmentOverride = SEG_OVERRIDE_FS;
diff --git a/tests/issues/x86-prefixes.yaml b/tests/issues/x86-prefixes.yaml
new file mode 100644
index 0000000000..2731d02beb
--- /dev/null
+++ b/tests/issues/x86-prefixes.yaml
@@ -0,0 +1,293 @@
+test_cases:
+  # Test segment override priority
+  -
+    input:
+      name: "x86-16: rightmost segment override should take priority"
+      bytes: [ 0x26, 0x65, 0x64, 0x3E, 0x65, 0x2E, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_16 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr cs:[bx + si], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_CS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-32: rightmost segment override should take priority"
+      bytes: [ 0x26, 0x65, 0x64, 0x3E, 0x65, 0x2E, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_32 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr cs:[eax], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_CS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-64: rightmost segment override should take priority"
+      bytes: [ 0x26, 0x65, 0x64, 0x3E, 0x65, 0x2E, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_64 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr gs:[rax], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_GS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-16: rightmost segment override should take priority"
+      bytes: [ 0x3E, 0x3E, 0x26, 0x36, 0x64, 0x36, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_16 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr ss:[bx + si], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_SS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-32: rightmost segment override should take priority"
+      bytes: [ 0x3E, 0x3E, 0x26, 0x36, 0x64, 0x36, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_32 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr ss:[eax], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_SS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-64: rightmost segment override should take priority"
+      bytes: [ 0x3E, 0x3E, 0x26, 0x36, 0x64, 0x36, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_64 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr fs:[rax], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_FS, X86_PREFIX_0, X86_PREFIX_0 ]
+  # Test segment override differences between 16/32 and 64-bit mode with ECDS and FS/GS
+  -
+    input:
+      name: "x86-16: ECSD segment overrides should override FS/GS segment overrides"
+      bytes: [ 0x64, 0x3E, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_16 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr ds:[bx + si], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_DS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-32: ECSD segment overrides should override FS/GS segment overrides"
+      bytes: [ 0x64, 0x3E, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_32 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr ds:[eax], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_DS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-64: ECSD segment overrides should be ignored and leave FS override intact"
+      bytes: [ 0x64, 0x3E, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_64 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr fs:[rax], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_FS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-64: ECSD segment overrides should be ignored"
+      bytes: [ 0x3E, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_64 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr [rax], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_DS, X86_PREFIX_0, X86_PREFIX_0 ]
+  # Test duplicate segment override prefixes
+  -
+    input:
+      name: "x86-16: Duplicate ES override prefixes should decode successfully"
+      bytes: [ 0x26, 0x26, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_16 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr es:[bx + si], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_ES, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-32: Duplicate ES override prefixes should decode successfully"
+      bytes: [ 0x26, 0x26, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_32 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr es:[eax], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_ES, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-64: Duplicate FS override prefixes should decode successfully"
+      bytes: [ 0x64, 0x64, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_64 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr fs:[rax], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_FS, X86_PREFIX_0, X86_PREFIX_0 ]
+  # Test invalid REX prefix
+  -
+    input:
+      name: "x86-64: Invalid REX prefix should preserve previous segment override"
+      bytes: [ 0x64, 0x40, 0x2E, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_64 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr fs:[rax], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_FS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-64: Invalid REX prefix should not add ECDS segment override"
+      bytes: [ 0x2E, 0x40, 0x2E, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_64 ]
+    expected:
+      insns:
+      -
+        asm_text: "add byte ptr [rax], al"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_CS, X86_PREFIX_0, X86_PREFIX_0 ]
+  # Test whether `notrack` is correctly decoded
+  -
+    input:
+      name: "x86-16: notrack should decode correctly"
+      bytes: [ 0x3E, 0xE8, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_16 ]
+    expected:
+      insns:
+      -
+        asm_text: "notrack call 4"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_DS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-32: notrack should decode correctly"
+      bytes: [ 0x3E, 0xE8, 0x00, 0x00, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_32 ]
+    expected:
+      insns:
+      -
+        asm_text: "notrack call 6"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_DS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-64: notrack should decode correctly"
+      bytes: [ 0x3E, 0xE8, 0x00, 0x00, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_64 ]
+    expected:
+      insns:
+      -
+        asm_text: "notrack call 6"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_DS, X86_PREFIX_0, X86_PREFIX_0 ]
+
+  -
+    input:
+      name: "x86-16: notrack should be applied when 0x3E is last segment override prefix"
+      bytes: [ 0x26, 0x64, 0x3E, 0xE8, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_16 ]
+    expected:
+      insns:
+      -
+        asm_text: "notrack call 6"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_DS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-32: notrack should be applied when 0x3E is last segment override prefix"
+      bytes: [ 0x26, 0x64, 0x3E, 0xE8, 0x00, 0x00, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_32 ]
+    expected:
+      insns:
+      -
+        asm_text: "notrack call 8"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_DS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-64: workaround: notrack should only be applied when 0x3E is last segment override prefix and no FS/GS segment override prefix is active"
+      bytes: [ 0x26, 0x64, 0x3E, 0xE8, 0x00, 0x00, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_64 ]
+    expected:
+      insns:
+      -
+        asm_text: "call 8"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_FS, X86_PREFIX_0, X86_PREFIX_0 ]
+  -
+    input:
+      name: "x86-64: workaround: notrack should only be applied when 0x3E is last segment override prefix and no FS/GS segment override prefix is active"
+      bytes: [ 0x26, 0x2E, 0x3E, 0xE8, 0x00, 0x00, 0x00, 0x00 ]
+      arch: "CS_ARCH_X86"
+      options: [ CS_OPT_DETAIL, CS_MODE_64 ]
+    expected:
+      insns:
+      -
+        asm_text: "notrack call 8"
+        details:
+          x86:
+            prefix: [ X86_PREFIX_0, X86_PREFIX_DS, X86_PREFIX_0, X86_PREFIX_0 ]
\ No newline at end of file