diff --git a/src/script/script.h b/src/script/script.h
--- a/src/script/script.h
+++ b/src/script/script.h
@@ -366,7 +366,8 @@
 
         std::vector<uint8_t> result;
         const bool neg = value < 0;
-        uint64_t absvalue = neg ? -value : value;
+        uint64_t absvalue = neg ? ~static_cast<uint64_t>(value) + 1
+                                : static_cast<uint64_t>(value);
 
         while (absvalue) {
             result.push_back(absvalue & 0xff);
diff --git a/src/test/fuzz/integer.cpp b/src/test/fuzz/integer.cpp
--- a/src/test/fuzz/integer.cpp
+++ b/src/test/fuzz/integer.cpp
@@ -164,13 +164,7 @@
 
     const CScriptNum script_num{i64};
     (void)script_num.getint();
-    // Avoid negation failure:
-    // script/script.h:332:35: runtime error: negation of -9223372036854775808
-    // cannot be represented in type 'int64_t' (aka 'long'); cast to an unsigned
-    // type to negate this value to itself
-    if (script_num != CScriptNum{std::numeric_limits<int64_t>::min()}) {
-        (void)script_num.getvch();
-    }
+    (void)script_num.getvch();
 
     const arith_uint256 au256 = UintToArith256(u256);
     assert(ArithToUint256(au256) == u256);
diff --git a/src/test/fuzz/scriptnum_ops.cpp b/src/test/fuzz/scriptnum_ops.cpp
--- a/src/test/fuzz/scriptnum_ops.cpp
+++ b/src/test/fuzz/scriptnum_ops.cpp
@@ -181,12 +181,6 @@
                 break;
         }
         (void)script_num.getint();
-        // Avoid negation failure:
-        // script/script.h:332:35: runtime error: negation of
-        // -9223372036854775808 cannot be represented in type 'int64_t' (aka
-        // 'long'); cast to an unsigned type to negate this value to itself
-        if (script_num != CScriptNum{std::numeric_limits<int64_t>::min()}) {
-            (void)script_num.getvch();
-        }
+        (void)script_num.getvch();
     }
 }