diff --git a/projects/unrar/build.sh b/projects/unrar/build.sh
index 94696828a..e4f65811c 100644
--- a/projects/unrar/build.sh
+++ b/projects/unrar/build.sh
@@ -15,6 +15,18 @@
 #
 ################################################################################
 
+# Fuzz introspector uses LDFLAGS, so ensure LDFLAGS
+# is always set for other sanitizer options.
+if [ "$SANITIZER" != "introspector" ]; then
+  export LDFLAGS=""
+else
+  # We need to add -flto flags because the makefile in unrar does not
+  # pass cxxflags, which holds the -flto flag from fuzz-introspector.
+  # This should probably be updated in the future, namely, including
+  # -flto into LDFLAGS in OSS-Fuzz fuzz-introspector builds.
+  export LDFLAGS="${LDFLAGS} -flto"
+fi
+
 UNRAR_DEFINES="-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DRAR_SMP -DRARDLL -DSILENT -DNOVOLUME"
 UNRAR_WNOS="-Wno-logical-op-parentheses -Wno-switch -Wno-dangling-else"
 UNRAR_SRC_DIR="$SRC/unrar"
@@ -25,7 +37,7 @@ CXXFLAGS="$CXXFLAGS -fno-sanitize=enum"
 
 # build 'lib'. This builds libunrar.a and libunrar.so
 # -fPIC is required for successful compilation.
-make CXX=$CXX CXXFLAGS="$CXXFLAGS -fPIC $UNRAR_DEFINES $UNRAR_WNOS" \
+make CXX=$CXX LDFLAGS="$LDFLAGS" CXXFLAGS="$CXXFLAGS -fPIC $UNRAR_DEFINES $UNRAR_WNOS" \
   -C $UNRAR_SRC_DIR lib
 
 # remove the .so file so that the linker links unrar statically.