diff --git a/.rustsec-ignore.txt b/.rustsec-ignore.txt
index 4bd22dd..8ef81c4 100644
--- a/.rustsec-ignore.txt
+++ b/.rustsec-ignore.txt
@@ -9,3 +9,11 @@ RUSTSEC-2024-0384
 # adler 1.0.2 affected by RUSTSEC-2025-0056 (unmaintained)
 # -> only used for anyhow backtraces
 RUSTSEC-2025-0056
+
+# crossbeam-epoch 0.9.18 affected by RUSTSEC-2026-0204 (Invalid
+# pointer dereference in `fmt::Pointer` impl for `Atomic` and `Shared`
+# when the underlying pointer is invalid)
+#
+# XXX should look into this. Affected versions: >=0.9.0, <0.9.20, and
+# 0.9.20 is just 1 month old, thus have to review.
+RUSTSEC-2026-0204
diff --git a/Cargo.lock b/Cargo.lock
index 965f337..a716c24 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -346,6 +346,24 @@ dependencies = [
  "adler",
 ]
 
+[[package]]
+name = "mockalloc"
+version = "0.1.2"
+source = "git+https://github.com/diggsey/mockalloc?rev=103439477d7e6acccef3c203730ed3009f3dec41#103439477d7e6acccef3c203730ed3009f3dec41"
+dependencies = [
+ "mockalloc-macros",
+]
+
+[[package]]
+name = "mockalloc-macros"
+version = "0.1.0"
+source = "git+https://github.com/diggsey/mockalloc?rev=103439477d7e6acccef3c203730ed3009f3dec41#103439477d7e6acccef3c203730ed3009f3dec41"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "nix"
 version = "0.24.3"
@@ -490,6 +508,7 @@ dependencies = [
  "clap-with-warnings",
  "derive_more",
  "lazy_static",
+ "mockalloc",
  "patchparser",
  "rayon",
  "regex",
diff --git a/Cargo.toml b/Cargo.toml
index c94c6a9..5f9978b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,5 +16,6 @@ clap = { version = "4", features = ["derive"] }
 clap-with-warnings = { version = "0.1.4" }
 derive_more = { version = "2.0.1", features = ["from", "from_str"] }
 lazy_static = "1.4"
+mockalloc = { git = "https://github.com/diggsey/mockalloc", rev = "103439477d7e6acccef3c203730ed3009f3dec41" }
 rayon = "1.10.0"
 regex = "1.4.6"
diff --git a/Makefile b/Makefile
index 187bd92..fed5bb6 100644
--- a/Makefile
+++ b/Makefile
@@ -32,7 +32,7 @@ test_integration_opt:
 test: cargo_test test_integration
 
 leak_test:
-	RUSTFLAGS="-Z sanitizer=leak" OUR_CARGO_FLAGS=+nightly make test
+	make test
 
 test_deny_warnings:
 	RUSTFLAGS="--deny warnings" make cargo_test
diff --git a/src/bin/test-split-patches-in-dir.rs b/src/bin/test-split-patches-in-dir.rs
index 1cc74f1..a69bbc8 100644
--- a/src/bin/test-split-patches-in-dir.rs
+++ b/src/bin/test-split-patches-in-dir.rs
@@ -1,4 +1,5 @@
 use std::{
+    alloc::System,
     fs::{self, File},
     io::{BufWriter, Write},
     os::unix::ffi::OsStrExt,
@@ -9,11 +10,15 @@ use std::{
 use anyhow::anyhow;
 use anyhow::{Context, Ok, Result};
 use clap_with_warnings::clap_with_warnings;
+use mockalloc::Mockalloc;
 use rayon::iter::{IntoParallelRefIterator, ParallelIterator};
 use split_patch::{
     core::split_patch, path_utils::path_remove_common_lead, split_options::SplitArgs,
 };
 
+#[global_allocator]
+static ALLOCATOR: Mockalloc<System> = Mockalloc(System);
+
 /// Test split patches in directory.
 ///
 /// For all files in `input-dir`, split them with `split-patch` into
@@ -32,7 +37,7 @@ pub struct TestArgs {
     output_base: PathBuf,
 }
 
-fn main() -> Result<()> {
+fn main_() -> Result<()> {
     let args = TestArgs::parse();
 
     let mut patch_files: Vec<PathBuf> = args
@@ -140,3 +145,24 @@ fn main() -> Result<()> {
 
     Ok(())
 }
+
+fn main() {
+    let mut exit_code = 0;
+    // assert_allocs does not allow non-() returns; makes sense since
+    // those allocations would be leaks and lead to a panic. But don't
+    // want to exit inside. Thus, pass the integer value out, let it
+    // check, then exit.
+    mockalloc::assert_allocs(|| {
+        // Need to set up our own rayon thread pool to ensure that it
+        // is being shut down before doing the leak check.
+        let pool = rayon::ThreadPoolBuilder::new()
+            .build().unwrap();
+        pool.install(|| {
+            if let Err(e) = main_() {
+                eprintln!("Error: {e:#}");
+                exit_code = 1;
+            }
+        });
+    });
+    exit(exit_code);
+}