diff --git a/docs/content/2026-news.md b/docs/content/2026-news.md
index d4143521..184158a0 100644
--- a/docs/content/2026-news.md
+++ b/docs/content/2026-news.md
@@ -1,6 +1,36 @@
 <span id="news-2026"></span>
 # Changelog - 2026
 
+## 25.3.0 - 2026-03-26
+
+### Bug Fixes
+
+- **HTTP/2 ASGI Body Duplication**: Fix request body being received twice in HTTP/2
+  ASGI requests, causing JSON parsing errors with "Extra data" messages
+  ([#3558](https://github.com/benoitc/gunicorn/issues/3558))
+
+- **ASGI Chunked EOF Handling**: Add `finish()` method to callback parser to handle
+  chunked encoding edge case where connection closes before final CRLF after zero-chunk
+
+### Security
+
+- **ASGI Parser Header Validation**: Add security checks per RFC 9110/9112:
+  - Reject duplicate Content-Length headers
+  - Reject requests with both Content-Length and Transfer-Encoding
+  - Reject chunked transfer encoding in HTTP/1.0
+  - Reject stacked chunked encoding
+  - Validate Transfer-Encoding values
+  - Strict chunk size validation
+
+### Changes
+
+- **Fast HTTP Parser**: Update to gunicorn_h1c >= 0.6.2 for `asgi_headers` property
+  which provides headers with lowercase names directly from the C parser
+
+- **ASGI PROXY Protocol**: Add PROXY protocol v1/v2 support to callback parser
+
+---
+
 ## 25.2.0 - 2026-03-24
 
 ### New Features
diff --git a/docs/content/news.md b/docs/content/news.md
index 5ac5b76e..6be3368d 100644
--- a/docs/content/news.md
+++ b/docs/content/news.md
@@ -1,6 +1,36 @@
 <span id="news"></span>
 # Changelog
 
+## 25.3.0 - 2026-03-26
+
+### Bug Fixes
+
+- **HTTP/2 ASGI Body Duplication**: Fix request body being received twice in HTTP/2
+  ASGI requests, causing JSON parsing errors with "Extra data" messages
+  ([#3558](https://github.com/benoitc/gunicorn/issues/3558))
+
+- **ASGI Chunked EOF Handling**: Add `finish()` method to callback parser to handle
+  chunked encoding edge case where connection closes before final CRLF after zero-chunk
+
+### Security
+
+- **ASGI Parser Header Validation**: Add security checks per RFC 9110/9112:
+  - Reject duplicate Content-Length headers
+  - Reject requests with both Content-Length and Transfer-Encoding
+  - Reject chunked transfer encoding in HTTP/1.0
+  - Reject stacked chunked encoding
+  - Validate Transfer-Encoding values
+  - Strict chunk size validation
+
+### Changes
+
+- **Fast HTTP Parser**: Update to gunicorn_h1c >= 0.6.2 for `asgi_headers` property
+  which provides headers with lowercase names directly from the C parser
+
+- **ASGI PROXY Protocol**: Add PROXY protocol v1/v2 support to callback parser
+
+---
+
 ## 25.2.0 - 2026-03-24
 
 ### New Features
diff --git a/gunicorn/__init__.py b/gunicorn/__init__.py
index 26a9e00a..6009fecc 100644
--- a/gunicorn/__init__.py
+++ b/gunicorn/__init__.py
@@ -2,7 +2,7 @@
 # This file is part of gunicorn released under the MIT license.
 # See the NOTICE for more information.
 
-version_info = (25, 2, 0)
+version_info = (25, 3, 0)
 __version__ = ".".join([str(v) for v in version_info])
 SERVER = "gunicorn"
 SERVER_SOFTWARE = "%s/%s" % (SERVER, __version__)
diff --git a/gunicorn/asgi/parser.py b/gunicorn/asgi/parser.py
index 818a71c6..a1f608a6 100644
--- a/gunicorn/asgi/parser.py
+++ b/gunicorn/asgi/parser.py
@@ -835,7 +835,9 @@ class CallbackRequest:
         req.version = parser.http_version
 
         # Headers - store both bytes (for ASGI scope) and strings (for compatibility)
-        req.headers_bytes = list(parser.headers)
+        # Use asgi_headers (lowercase names) if available (fast parser >= 0.6.2),
+        # otherwise fall back to headers (Python parser already uses lowercase)
+        req.headers_bytes = list(getattr(parser, 'asgi_headers', None) or parser.headers)
         req.headers = [
             (n.decode('latin-1').upper(), v.decode('latin-1'))
             for n, v in parser.headers
diff --git a/pyproject.toml b/pyproject.toml
index ba579434..07ae3e41 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -53,7 +53,11 @@ tornado = ["tornado>=6.5.0"]
 gthread = []
 setproctitle = ["setproctitle"]
 http2 = ["h2>=4.1.0"]
-fast = ["gunicorn_h1c>=0.6.0"]
+
+
+
+fast = ["gunicorn_h1c>=0.6.2"]
+
 testing = [
     "gevent>=24.10.1",
     "eventlet>=0.40.3",
diff --git a/requirements_test.txt b/requirements_test.txt
index 3093c4e6..4d26756a 100644
--- a/requirements_test.txt
+++ b/requirements_test.txt
@@ -3,4 +3,4 @@ coverage
 pytest>=7.2.0
 pytest-cov
 pytest-asyncio
-gunicorn_h1c>=0.6.0
+gunicorn_h1c>=0.6.2
diff --git a/tests/conftest.py b/tests/conftest.py
index 018ffbc5..c3824279 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -21,7 +21,7 @@ def http_parser(request):
     """Parametrize tests over http_parser implementations."""
     if request.param == "fast":
         gunicorn_h1c = pytest.importorskip("gunicorn_h1c", reason="gunicorn_h1c required")
-        # Require >= 0.6.0 for header framing validation
-        if not hasattr(gunicorn_h1c, 'InvalidHeader'):
-            pytest.skip("gunicorn_h1c >= 0.6.0 required")
+        # Require >= 0.6.2 for asgi_headers support
+        if not hasattr(gunicorn_h1c.H1CProtocol, 'asgi_headers'):
+            pytest.skip("gunicorn_h1c >= 0.6.2 required")
     return request.param