diff --git a/.cargo/config.toml b/.cargo/config.toml
index 635229119f8..ceb8134791c 100644
--- a/.cargo/config.toml
+++ b/.cargo/config.toml
@@ -6,3 +6,19 @@ rustflags = "-C link-args=-Wl,--stack,8000000"
 
 [target.wasm32-unknown-unknown]
 rustflags = ["--cfg=getrandom_backend=\"wasm_js\""]
+
+# Enforce a 64 MB memory cap and 1 MB stack limit for WASI targets.
+# Without these, the WASM heap can grow unboundedly (e.g., a simple
+# `a = 1` allocated ~79 MB) and crash on constrained runtimes like wasmi.
+# See issue #4989.
+[target.wasm32-wasip1]
+rustflags = [
+    "-C", "link-arg=--max-memory=67108864",
+    "-C", "link-arg=-zstack-size=1048576",
+]
+
+[target.wasm32-wasip2]
+rustflags = [
+    "-C", "link-arg=--max-memory=67108864",
+    "-C", "link-arg=-zstack-size=1048576",
+]
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 2a6a5264c21..1da4cb1ba64 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -790,11 +790,11 @@ jobs:
           clang: true
 
       - name: build rustpython
-        run: cargo build --release --target wasm32-wasip1 --no-default-features --features freeze-stdlib,stdlib,stdio,importlib,host_env --verbose
+        run: cargo build --profile wasm-release --target wasm32-wasip1 --no-default-features --features freeze-stdlib,stdlib,stdio,importlib,host_env --verbose
       - name: run snippets
-        run: wasmer run --dir "$(pwd)" target/wasm32-wasip1/release/rustpython.wasm -- "$(pwd)/extra_tests/snippets/stdlib_random.py"
+        run: wasmer run --dir "$(pwd)" target/wasm32-wasip1/wasm-release/rustpython.wasm -- "$(pwd)/extra_tests/snippets/stdlib_random.py"
       - name: run cpython unittest
-        run: wasmer run --dir "$(pwd)" target/wasm32-wasip1/release/rustpython.wasm -- "$(pwd)/Lib/test/test_int.py"
+        run: wasmer run --dir "$(pwd)" target/wasm32-wasip1/wasm-release/rustpython.wasm -- "$(pwd)/Lib/test/test_int.py"
 
   cargo_doc:
     needs:
@@ -831,3 +831,4 @@ jobs:
 
       - name: cargo doc
         run: cargo doc --locked
+
diff --git a/Cargo.toml b/Cargo.toml
index a63656ebea7..c0ec19e0fa1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -117,6 +117,14 @@ opt-level = 3
 [profile.release]
 lto = "thin"
 
+[profile.wasm-release]
+inherits = "release"
+opt-level = "s"
+lto = true
+codegen-units = 1
+strip = true
+panic = "abort"
+
 [patch.crates-io]
 parking_lot_core = { git = "https://github.com/youknowone/parking_lot", branch = "rustpython" }
 # REDOX START, Uncomment when you want to compile/check with redoxer
diff --git a/crates/vm/src/datastack.rs b/crates/vm/src/datastack.rs
index f2ffb74894a..7529263ac7e 100644
--- a/crates/vm/src/datastack.rs
+++ b/crates/vm/src/datastack.rs
@@ -9,7 +9,12 @@ use core::alloc::Layout;
 use core::ptr;
 
 /// Minimum chunk size in bytes (`_PY_DATA_STACK_CHUNK_SIZE`).
-const MIN_CHUNK_SIZE: usize = 16 * 1024;
+/// Smaller on WASM (4 KB) to reduce initial memory footprint; 16 KB otherwise.
+const MIN_CHUNK_SIZE: usize = if cfg!(target_arch = "wasm32") {
+    4 * 1024
+} else {
+    16 * 1024
+};
 
 /// Extra headroom (in bytes) to avoid allocating a new chunk for the next
 /// frame right after growing.