diff --git a/.github/workflows/ci-post-merge.yml b/.github/workflows/ci-post-merge.yml
index 918765d63..4baf90392 100644
--- a/.github/workflows/ci-post-merge.yml
+++ b/.github/workflows/ci-post-merge.yml
@@ -49,7 +49,7 @@ jobs:
           toolchain: ${{ matrix.version.version }}
 
       - name: Install just, cargo-hack, cargo-nextest, cargo-ci-cache-clean
-        uses: taiki-e/install-action@06203676c62f0d3c765be3f2fcfbebbcb02d09f5 # v2.69.6
+        uses: taiki-e/install-action@fd0f63e180a477d7434580b6d80817978b9ff2b8 # v2.70.1
         with:
           tool: just,cargo-hack,cargo-nextest,cargo-ci-cache-clean
 
@@ -83,7 +83,7 @@ jobs:
         uses: actions-rust-lang/setup-rust-toolchain@150fca883cd4034361b621bd4e6a9d34e5143606 # v1.15.4
 
       - name: Install just, cargo-hack
-        uses: taiki-e/install-action@06203676c62f0d3c765be3f2fcfbebbcb02d09f5 # v2.69.6
+        uses: taiki-e/install-action@fd0f63e180a477d7434580b6d80817978b9ff2b8 # v2.70.1
         with:
           tool: just,cargo-hack
 
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f0487ab80..9939e4dad 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -64,7 +64,7 @@ jobs:
           toolchain: ${{ matrix.version.version }}
 
       - name: Install just, cargo-hack, cargo-nextest, cargo-ci-cache-clean
-        uses: taiki-e/install-action@06203676c62f0d3c765be3f2fcfbebbcb02d09f5 # v2.69.6
+        uses: taiki-e/install-action@fd0f63e180a477d7434580b6d80817978b9ff2b8 # v2.70.1
         with:
           tool: just,cargo-hack,cargo-nextest,cargo-ci-cache-clean
 
@@ -117,7 +117,7 @@ jobs:
           toolchain: nightly
 
       - name: Install just
-        uses: taiki-e/install-action@06203676c62f0d3c765be3f2fcfbebbcb02d09f5 # v2.69.6
+        uses: taiki-e/install-action@fd0f63e180a477d7434580b6d80817978b9ff2b8 # v2.70.1
         with:
           tool: just
 
diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index 36ffa2a6d..0acfcee48 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -24,7 +24,7 @@ jobs:
           components: llvm-tools
 
       - name: Install just, cargo-llvm-cov, cargo-nextest
-        uses: taiki-e/install-action@06203676c62f0d3c765be3f2fcfbebbcb02d09f5 # v2.69.6
+        uses: taiki-e/install-action@fd0f63e180a477d7434580b6d80817978b9ff2b8 # v2.70.1
         with:
           tool: just,cargo-llvm-cov,cargo-nextest
 
@@ -32,7 +32,7 @@ jobs:
         run: just test-coverage-codecov
 
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@1af58845a975a7985b0beb0cbe6fbbb71a41dbad # v5.5.3
+        uses: codecov/codecov-action@57e3a136b779b570ffcdbf80b3bdc90e7fab3de2 # v6.0.0
         with:
           files: codecov.json
           fail_ci_if_error: true
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 0250424bf..e4d65f508 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -77,12 +77,12 @@ jobs:
           toolchain: ${{ vars.RUST_VERSION_EXTERNAL_TYPES }}
 
       - name: Install just
-        uses: taiki-e/install-action@06203676c62f0d3c765be3f2fcfbebbcb02d09f5 # v2.69.6
+        uses: taiki-e/install-action@fd0f63e180a477d7434580b6d80817978b9ff2b8 # v2.70.1
         with:
           tool: just
 
       - name: Install cargo-check-external-types
-        uses: taiki-e/cache-cargo-install-action@59027ebf20a9617c4e819eb53ccd2673cb162b89 # v3.0.3
+        uses: taiki-e/cache-cargo-install-action@a08630789e5d5e43eddea7354c8bbd11755fb3d2 # v3.0.4
         with:
           tool: cargo-check-external-types
 
diff --git a/Cargo.lock b/Cargo.lock
index 5602423e9..be7a17dab 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -473,9 +473,9 @@ checksum = "4b46cbb362ab8752921c97e041f5e366ee6297bd428a31275b9fcf1e380f7299"
 
 [[package]]
 name = "anstream"
-version = "0.6.21"
+version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "43d5b281e737544384e969a5ccad3f1cdd24b48086a0fc1b2a5262a26b8f4f4a"
+checksum = "824a212faf96e9acacdbd09febd34438f8f711fb84e09a8916013cd7815ca28d"
 dependencies = [
  "anstyle",
  "anstyle-parse",
@@ -494,9 +494,9 @@ checksum = "5192cca8006f1fd4f7237516f40fa183bb07f8fbdfedaa0036de5ea9b0b45e78"
 
 [[package]]
 name = "anstyle-parse"
-version = "0.2.7"
+version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4e7644824f0aa2c7b9384579234ef10eb7efb6a0deb83f9630a49594dd9c15c2"
+checksum = "52ce7f38b242319f7cabaa6813055467063ecdc9d355bbb4ce0c68908cd8130e"
 dependencies = [
  "utf8parse",
 ]
@@ -1187,9 +1187,9 @@ dependencies = [
 
 [[package]]
 name = "env_logger"
-version = "0.11.9"
+version = "0.11.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b2daee4ea451f429a58296525ddf28b45a3b64f1acf6587e2067437bb11e218d"
+checksum = "0621c04f2196ac3f488dd583365b9c09be011a4ab8b9f37248ffcc8f6198b56a"
 dependencies = [
  "anstream",
  "anstyle",
@@ -1770,9 +1770,9 @@ checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
 
 [[package]]
 name = "jiff"
-version = "0.2.18"
+version = "0.2.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e67e8da4c49d6d9909fe03361f9b620f58898859f5c7aded68351e85e71ecf50"
+checksum = "1a3546dc96b6d42c5f24902af9e2538e82e39ad350b0c766eb3fbf2d8f3d8359"
 dependencies = [
  "jiff-static",
  "log",
@@ -1783,9 +1783,9 @@ dependencies = [
 
 [[package]]
 name = "jiff-static"
-version = "0.2.18"
+version = "0.2.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e0c84ee7f197eca9a86c6fd6cb771e55eb991632f15f2bc3ca6ec838929e6e78"
+checksum = "2a8c8b344124222efd714b73bb41f8b5120b27a7cc1c75593a6ff768d9d05aa4"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/actix-web/CHANGES.md b/actix-web/CHANGES.md
index 59901dfd4..72f541653 100644
--- a/actix-web/CHANGES.md
+++ b/actix-web/CHANGES.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Enable dual-stack IPv6 sockets on Windows when possible so that Actix-created listeners bound to `[::]` also accept IPv4 connections.
 - Panic when calling `Route::to()` or `Route::service()` after `Route::wrap()` to prevent silently dropping route middleware. [#3944]
 - Fix `HttpRequest::{match_pattern,match_name}` reporting path-only matches when route guards disambiguate overlapping resources. [#3346]
 - Fix `Readlines` handling of lines split across payload chunks so combined line limits are enforced and complete lines are yielded.
diff --git a/actix-web/src/http/header/content_length.rs b/actix-web/src/http/header/content_length.rs
index 557c7c9f5..1bb5545ae 100644
--- a/actix-web/src/http/header/content_length.rs
+++ b/actix-web/src/http/header/content_length.rs
@@ -214,7 +214,11 @@ mod tests {
         assert_parse_eq::<ContentLength, _, _>([" 0"], ContentLength(0));
         assert_parse_eq::<ContentLength, _, _>(["0 "], ContentLength(0));
         assert_parse_eq::<ContentLength, _, _>([" 0 "], ContentLength(0));
+    }
 
+    #[cfg(target_pointer_width = "64")]
+    #[test]
+    fn good_header_max_usize() {
         // large value (2^64 - 1)
         assert_parse_eq::<ContentLength, _, _>(
             ["18446744073709551615"],
diff --git a/actix-web/src/server.rs b/actix-web/src/server.rs
index c0bec7f05..2f52b21fb 100644
--- a/actix-web/src/server.rs
+++ b/actix-web/src/server.rs
@@ -445,6 +445,14 @@ where
     /// Using a bind address of `0.0.0.0`, which signals to use all interfaces, may also multiple
     /// the number of instantiations in a similar way.
     ///
+    /// # Dual-Stack IPv6
+    ///
+    /// On Windows, when this method creates an IPv6 listener (e.g., for `[::]:8080`), this
+    /// attempts to enable dual-stack mode so the socket can accept both IPv4 and IPv6
+    /// connections. On Linux and macOS, dual-stack is typically already the OS default. If you
+    /// need IPv6-only behavior on Windows, create the listener manually and pass it to
+    /// [`listen()`](Self::listen()).
+    ///
     /// # Typical Usage
     ///
     /// In general, use `127.0.0.1:<port>` when testing locally and `0.0.0.0:<port>` when deploying
@@ -1259,6 +1267,14 @@ fn create_tcp_listener(addr: net::SocketAddr, backlog: u32) -> io::Result<net::T
     {
         socket.set_reuse_address(true)?;
     }
+    // On Windows, IPV6_V6ONLY defaults to true, preventing IPv6 sockets from accepting IPv4
+    // connections. Set it to false so that binding to [::] also accepts IPv4 traffic.
+    #[cfg(windows)]
+    if addr.is_ipv6() {
+        if let Err(err) = socket.set_only_v6(false) {
+            log::warn!("failed to set IPV6_V6ONLY=false: {err}");
+        }
+    }
     socket.bind(&addr.into())?;
     // clamp backlog to max u32 that fits in i32 range
     let backlog = cmp::min(backlog, i32::MAX as u32) as i32;
diff --git a/actix-web/tests/test_httpserver.rs b/actix-web/tests/test_httpserver.rs
index c4f87fabb..44283ebd4 100644
--- a/actix-web/tests/test_httpserver.rs
+++ b/actix-web/tests/test_httpserver.rs
@@ -217,3 +217,48 @@ async fn test_tcp_nodelay_enabled() {
 async fn test_tcp_nodelay_disabled() {
     assert_tcp_nodelay_config(false).await;
 }
+
+#[actix_rt::test]
+#[cfg(windows)]
+async fn test_dual_stack_ipv6_on_windows() {
+    let (tx, rx) = mpsc::channel();
+
+    thread::spawn(move || {
+        actix_rt::System::new()
+            .block_on(async {
+                let srv = HttpServer::new(|| {
+                    App::new().service(
+                        web::resource("/")
+                            .route(web::to(|| async { HttpResponse::Ok().body("test") })),
+                    )
+                })
+                .workers(1)
+                .disable_signals()
+                .bind("[::]:0")
+                .unwrap();
+
+                let port = srv.addrs()[0].port();
+                let srv = srv.run();
+
+                tx.send((srv.handle(), port)).unwrap();
+                srv.await
+            })
+            .unwrap();
+    });
+
+    let (srv, port) = rx.recv().unwrap();
+
+    let client = awc::Client::builder()
+        .connector(awc::Connector::new().timeout(Duration::from_secs(1)))
+        .finish();
+
+    let response = client
+        .get(format!("http://127.0.0.1:{port}"))
+        .send()
+        .await
+        .unwrap();
+
+    assert!(response.status().is_success());
+
+    srv.stop(false).await;
+}