diff --git a/.github/workflows/continuous_integration.yml b/.github/workflows/continuous_integration.yml
index a7a1c662..b140b907 100644
--- a/.github/workflows/continuous_integration.yml
+++ b/.github/workflows/continuous_integration.yml
@@ -51,7 +51,7 @@ jobs:
       matrix:
         compiler: [{cc: gcc, cxx: g++}]
         cmake_build_type: [Debug]
-        flags: ['-fsanitize=address', '-fsanitize=thread']
+        flags: ['-fsanitize=address', '-fsanitize=thread', '-fsanitize=undefined']
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
       - uses: lukka/get-cmake@983956e4a5edce90f0dfcc38c1543077e668402b # v3.30.0
@@ -82,8 +82,12 @@ jobs:
       - name: Install
         run: cmake --install build --prefix build/install
       - name: Test
+        env:
+          UBSAN_OPTIONS: 'halt_on_error=1:print_stacktrace=1'
         run: ctest --output-on-failure --test-dir build
       - name: Test (standalone)
+        env:
+          UBSAN_OPTIONS: halt_on_error=1:print_stacktrace=1
         run: cd Test && ./runtests
 
   # Ensure we can compile/run on an older distro
diff --git a/glslang/HLSL/hlslParseHelper.cpp b/glslang/HLSL/hlslParseHelper.cpp
index 0fd724d0..c7a40f3b 100644
--- a/glslang/HLSL/hlslParseHelper.cpp
+++ b/glslang/HLSL/hlslParseHelper.cpp
@@ -6059,7 +6059,7 @@ void HlslParseContext::builtInOpCheck(const TSourceLoc& loc, const TFunction& fn
         unaryArg = callNode.getAsUnaryNode()->getOperand();
         arg0 = unaryArg;
     }
-    const TIntermSequence& aggArgs = *argp;  // only valid when unaryArg is nullptr
+    const TIntermSequence& aggArgs = argp ? *argp : TIntermSequence();  // only valid when unaryArg is nullptr
 
     switch (callNode.getOp()) {
     case EOpTextureGather:
diff --git a/glslang/MachineIndependent/Constant.cpp b/glslang/MachineIndependent/Constant.cpp
index 1f96129b..7a9fb2ed 100644
--- a/glslang/MachineIndependent/Constant.cpp
+++ b/glslang/MachineIndependent/Constant.cpp
@@ -507,7 +507,11 @@ TIntermTyped* TIntermConstantUnion::fold(TOperator op, const TType& returnType)
             case EbtUint8: newConstArray[i].setU8Const(static_cast<unsigned int>(-static_cast<signed int>(unionArray[i].getU8Const())));  break;
             case EbtInt16: newConstArray[i].setI16Const(-unionArray[i].getI16Const()); break;
             case EbtUint16:newConstArray[i].setU16Const(static_cast<unsigned int>(-static_cast<signed int>(unionArray[i].getU16Const())));  break;
-            case EbtInt64: newConstArray[i].setI64Const(-unionArray[i].getI64Const()); break;
+            case EbtInt64: {
+                int64_t i64val = unionArray[i].getI64Const();
+                newConstArray[i].setI64Const(i64val == INT64_MIN ? INT64_MIN : -i64val);
+                break;
+            }
             case EbtUint64: newConstArray[i].setU64Const(static_cast<unsigned long long>(-static_cast<long long>(unionArray[i].getU64Const())));  break;
             default:
                 return nullptr;
diff --git a/glslang/MachineIndependent/localintermediate.h b/glslang/MachineIndependent/localintermediate.h
index 2a24cdaf..31b13f16 100644
--- a/glslang/MachineIndependent/localintermediate.h
+++ b/glslang/MachineIndependent/localintermediate.h
@@ -99,7 +99,8 @@ private:
 // A "call" is a pair: <caller, callee>.
 // There can be duplicates. General assumption is the list is small.
 struct TCall {
-    TCall(const TString& pCaller, const TString& pCallee) : caller(pCaller), callee(pCallee) { }
+    TCall(const TString& pCaller, const TString& pCallee)
+        : caller(pCaller), callee(pCallee), visited(false), currentPath(false), errorGiven(false) { }
     TString caller;
     TString callee;
     bool visited;
diff --git a/glslang/MachineIndependent/preprocessor/Pp.cpp b/glslang/MachineIndependent/preprocessor/Pp.cpp
index 5f18c4e9..56f1f0b3 100644
--- a/glslang/MachineIndependent/preprocessor/Pp.cpp
+++ b/glslang/MachineIndependent/preprocessor/Pp.cpp
@@ -374,7 +374,7 @@ namespace {
     int op_div(int a, int b) { return a == INT_MIN && b == -1 ? 0 : a / b; }
     int op_mod(int a, int b) { return a == INT_MIN && b == -1 ? 0 : a % b; }
     int op_pos(int a) { return a; }
-    int op_neg(int a) { return -a; }
+    int op_neg(int a) { return a == INT_MIN ? INT_MIN : -a; }
     int op_cmpl(int a) { return ~a; }
     int op_not(int a) { return !a; }