diff --git a/lib/std/tar.zig b/lib/std/tar.zig
index e0a50a84cb..e295585bf3 100644
--- a/lib/std/tar.zig
+++ b/lib/std/tar.zig
@@ -300,7 +300,7 @@ fn Iterator(comptime ReaderType: type) type {
         }
 
         inline fn readString(self: *Self, size: usize, buffer: []u8) ![]const u8 {
-            assert(buffer.len >= size);
+            if (size > buffer.len) return error.TarCorruptInput;
             const buf = buffer[0..size];
             try self.reader.readNoEof(buf);
             return nullStr(buf);
diff --git a/lib/std/tar/test.zig b/lib/std/tar/test.zig
index 82c73e2546..f77b8a778a 100644
--- a/lib/std/tar/test.zig
+++ b/lib/std/tar/test.zig
@@ -313,6 +313,10 @@ test "tar run Go test cases" {
                 },
             },
         },
+        .{
+            .data = @embedFile("testdata/fuzz1.tar"),
+            .err = error.TarCorruptInput,
+        },
     };
 
     for (cases) |case| {
diff --git a/lib/std/tar/testdata/fuzz1.tar b/lib/std/tar/testdata/fuzz1.tar
new file mode 100644
index 0000000000..545949b82b
Binary files /dev/null and b/lib/std/tar/testdata/fuzz1.tar differ