diff --git a/test/fuzzer/lit.cfg.py b/test/fuzzer/lit.cfg.py
index 00871b8..d114ae7 100644
--- a/test/fuzzer/lit.cfg.py
+++ b/test/fuzzer/lit.cfg.py
@@ -61,6 +61,8 @@
 libfuzzer_src_root = os.path.join(config.compiler_rt_src_root, "lib", "fuzzer")
 config.substitutions.append(('%libfuzzer_src', libfuzzer_src_root))
 
+config.substitutions.append(('%python', '"%s"' % (sys.executable)))
+
 def generate_compiler_cmd(is_cpp=True, fuzzer_enabled=True, msan_enabled=False):
   compiler_cmd = config.clang
   extra_cmd = config.target_flags
diff --git a/test/fuzzer/trace-malloc-unbalanced.test b/test/fuzzer/trace-malloc-unbalanced.test
index c7b4632..395386a 100644
--- a/test/fuzzer/trace-malloc-unbalanced.test
+++ b/test/fuzzer/trace-malloc-unbalanced.test
@@ -8,10 +8,10 @@
 
 # Specify python because we can't use the shebang line on Windows.
 RUN: %run %t-TraceMallocTest -seed=1 -trace_malloc=1 -runs=200 2>&1 | \
-RUN:    python %libfuzzer_src/scripts/unbalanced_allocs.py --skip=5 | FileCheck %s
+RUN:    %python %libfuzzer_src/scripts/unbalanced_allocs.py --skip=5 | FileCheck %s
 
 RUN: %run %t-TraceMallocTest -seed=1 -trace_malloc=2 -runs=200 2>&1 | \
-RUN:    python %libfuzzer_src/scripts/unbalanced_allocs.py --skip=5 | FileCheck %s --check-prefixes=CHECK,CHECK2
+RUN:    %python %libfuzzer_src/scripts/unbalanced_allocs.py --skip=5 | FileCheck %s --check-prefixes=CHECK,CHECK2
 
 CHECK: MallocFreeTracer: START
 # Behavior of the format string "%p" is implementation defined. Account for the