diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
@@ -528,8 +528,23 @@
   if (PrologueErr)
     return PrologueErr;
 
-  const uint64_t EndOffset =
-      DebugLineOffset + Prologue.TotalLength + Prologue.sizeofTotalLength();
+  uint64_t ProgramLength = Prologue.TotalLength + Prologue.sizeofTotalLength();
+  if (!DebugLineData.isValidOffsetForDataOfSize(DebugLineOffset,
+                                                ProgramLength)) {
+    assert(DebugLineData.size() > DebugLineOffset &&
+           "prologue parsing should handle invalid offset");
+    uint64_t BytesRemaining = DebugLineData.size() - DebugLineOffset;
+    RecoverableErrorCallback(
+        createStringError(errc::invalid_argument,
+                          "line table program with offset 0x%8.8" PRIx64
+                          " has length 0x%8.8" PRIx64 " but only 0x%8.8" PRIx64
+                          " bytes are available",
+                          DebugLineOffset, ProgramLength, BytesRemaining));
+    // Continue by capping the length at the number of remaining bytes.
+    ProgramLength = BytesRemaining;
+  }
+
+  const uint64_t EndOffset = DebugLineOffset + ProgramLength;
 
   // See if we should tell the data extractor the address size.
   if (DebugLineData.getAddressSize() == 0)
diff --git a/llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp b/llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp
--- a/llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp
+++ b/llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp
@@ -438,6 +438,35 @@
       "0x00000030 expected 0x02 found 0x01");
 }
 
+TEST_F(DebugLineBasicFixture, ErrorForUnitLengthTooLarge) {
+  if (!setupGenerator())
+    return;
+
+  LineTable &Padding = Gen->addLineTable();
+  // Add some padding to show that a non-zero offset is handled correctly.
+  Padding.setCustomPrologue({{0, LineTable::Byte}});
+  LineTable &LT = Gen->addLineTable();
+  LT.addStandardOpcode(DW_LNS_copy, {});
+  LT.addStandardOpcode(DW_LNS_const_add_pc, {});
+  LT.addExtendedOpcode(1, DW_LNE_end_sequence, {});
+  DWARFDebugLine::Prologue Prologue = LT.createBasicPrologue();
+  // Set the total length to 1 higher than the actual length. The program body
+  // has size 5.
+  Prologue.TotalLength += 6;
+  LT.setPrologue(Prologue);
+
+  generate();
+
+  auto ExpectedLineTable = Line.getOrParseLineTable(LineData, 1, *Context,
+                                                    nullptr, RecordRecoverable);
+  checkError("line table program with offset 0x00000001 has length 0x00000034 "
+             "but only 0x00000033 bytes are available",
+             std::move(Recoverable));
+  ASSERT_THAT_EXPECTED(ExpectedLineTable, Succeeded());
+  EXPECT_EQ((*ExpectedLineTable)->Rows.size(), 2u);
+  EXPECT_EQ((*ExpectedLineTable)->Sequences.size(), 1u);
+}
+
 TEST_F(DebugLineBasicFixture, ErrorForMismatchedAddressSize) {
   if (!setupGenerator())
     return;