diff --git a/src/link/MachO.zig b/src/link/MachO.zig
index 3981fc0f7c..1ab71b6a5c 100644
--- a/src/link/MachO.zig
+++ b/src/link/MachO.zig
@@ -3606,17 +3606,25 @@ fn writeSymtab(self: *MachO) !SymtabCtx {
 }
 
 fn writeStrtab(self: *MachO) !void {
+    const gpa = self.base.allocator;
     const seg = self.getLinkeditSegmentPtr();
-    const offset = mem.alignForwardGeneric(u64, seg.fileoff + seg.filesize, @alignOf(u64));
+    const offset = seg.fileoff + seg.filesize;
+    assert(mem.isAlignedGeneric(u64, offset, @alignOf(u64)));
     const needed_size = self.strtab.buffer.items.len;
-    seg.filesize = offset + needed_size - seg.fileoff;
+    const needed_size_aligned = mem.alignForwardGeneric(u64, needed_size, @alignOf(u64));
+    seg.filesize = offset + needed_size_aligned - seg.fileoff;
 
-    log.debug("writing string table from 0x{x} to 0x{x}", .{ offset, offset + needed_size });
+    log.debug("writing string table from 0x{x} to 0x{x}", .{ offset, offset + needed_size_aligned });
 
-    try self.base.file.?.pwriteAll(self.strtab.buffer.items, offset);
+    const buffer = try gpa.alloc(u8, needed_size_aligned);
+    defer gpa.free(buffer);
+    mem.set(u8, buffer, 0);
+    mem.copy(u8, buffer, self.strtab.buffer.items);
+
+    try self.base.file.?.pwriteAll(buffer, offset);
 
     self.symtab_cmd.stroff = @intCast(u32, offset);
-    self.symtab_cmd.strsize = @intCast(u32, needed_size);
+    self.symtab_cmd.strsize = @intCast(u32, needed_size_aligned);
 }
 
 const SymtabCtx = struct {
diff --git a/src/link/MachO/zld.zig b/src/link/MachO/zld.zig
index 400985c4d7..2cf1f34743 100644
--- a/src/link/MachO/zld.zig
+++ b/src/link/MachO/zld.zig
@@ -2613,16 +2613,23 @@ pub const Zld = struct {
 
     fn writeStrtab(self: *Zld) !void {
         const seg = self.getLinkeditSegmentPtr();
-        const offset = mem.alignForwardGeneric(u64, seg.fileoff + seg.filesize, @alignOf(u64));
+        const offset = seg.fileoff + seg.filesize;
+        assert(mem.isAlignedGeneric(u64, offset, @alignOf(u64)));
         const needed_size = self.strtab.buffer.items.len;
-        seg.filesize = offset + needed_size - seg.fileoff;
+        const needed_size_aligned = mem.alignForwardGeneric(u64, needed_size, @alignOf(u64));
+        seg.filesize = offset + needed_size_aligned - seg.fileoff;
 
-        log.debug("writing string table from 0x{x} to 0x{x}", .{ offset, offset + needed_size });
+        log.debug("writing string table from 0x{x} to 0x{x}", .{ offset, offset + needed_size_aligned });
 
-        try self.file.pwriteAll(self.strtab.buffer.items, offset);
+        const buffer = try self.gpa.alloc(u8, needed_size_aligned);
+        defer self.gpa.free(buffer);
+        mem.set(u8, buffer, 0);
+        mem.copy(u8, buffer, self.strtab.buffer.items);
+
+        try self.file.pwriteAll(buffer, offset);
 
         self.symtab_cmd.stroff = @intCast(u32, offset);
-        self.symtab_cmd.strsize = @intCast(u32, needed_size);
+        self.symtab_cmd.strsize = @intCast(u32, needed_size_aligned);
     }
 
     const SymtabCtx = struct {