diff --git a/kraken-std/.changelog/_unreleased.toml b/kraken-std/.changelog/_unreleased.toml
index b6e3925e..ae336f83 100644
--- a/kraken-std/.changelog/_unreleased.toml
+++ b/kraken-std/.changelog/_unreleased.toml
@@ -11,3 +11,9 @@ type = "improvement"
 description = "Support pytest coverage."
 author = "benjamin.poumarede@helsing.ai"
 pr = "https://github.com/kraken-build/kraken-build/pull/48"
+
+[[entries]]
+id = "b240870c-57c7-408a-a8f7-ee9db06fb475"
+type = "improvement"
+description = "Add `--no-http2` to the mitmproxy when invoked via the Cargo auth proxy task. This is to work around an issue with Cargo HTTP/2 multi-plexing (see https://github.com/rust-lang/cargo/issues/12202)."
+author = "@NiklasRosenstein"
diff --git a/kraken-std/src/kraken/std/cargo/tasks/cargo_auth_proxy_task.py b/kraken-std/src/kraken/std/cargo/tasks/cargo_auth_proxy_task.py
index 0d19d1c8..4c9b221b 100644
--- a/kraken-std/src/kraken/std/cargo/tasks/cargo_auth_proxy_task.py
+++ b/kraken-std/src/kraken/std/cargo/tasks/cargo_auth_proxy_task.py
@@ -3,7 +3,7 @@
 import contextlib
 import logging
 import time
-from collections.abc import Iterator
+from collections.abc import Iterator, Sequence
 from pathlib import Path
 from urllib.parse import urlparse
 
@@ -41,6 +41,11 @@ class CargoAuthProxyTask(BackgroundTask):
     #: The number of seconds to wait after the proxy started.
     startup_wait_time: Property[float] = Property.default(1.0)
 
+    #: Additional args for the mitmproxy.
+    #: We pass `--no-http2` by default as that breaks Cargo HTTP/2 multiplexing. See
+    #: https://github.com/rust-lang/cargo/issues/12202
+    mitmproxy_additional_args: Property[Sequence[str]] = Property.default_factory(lambda: ["--no-http2"])
+
     @contextlib.contextmanager
     def _inject_config(self) -> Iterator[None]:
         """Injects the proxy URL and cert file into the Cargo and Git configuration."""
@@ -94,7 +99,7 @@ def start_background_task(self, exit_stack: contextlib.ExitStack) -> TaskStatus:
             host = not_none(urlparse(registry.index).hostname)
             auth[host] = registry.read_credentials
 
-        proxy_url, cert_file = start_mitmweb_proxy(auth=auth)
+        proxy_url, cert_file = start_mitmweb_proxy(auth=auth, additional_args=self.mitmproxy_additional_args.get())
         self.proxy_url.set(proxy_url)
         self.proxy_cert_file.set(cert_file)
         exit_stack.callback(lambda: self.proxy_url.clear())
diff --git a/kraken-std/src/kraken/std/mitm/__init__.py b/kraken-std/src/kraken/std/mitm/__init__.py
index d89c8d5f..8d5752ad 100644
--- a/kraken-std/src/kraken/std/mitm/__init__.py
+++ b/kraken-std/src/kraken/std/mitm/__init__.py
@@ -9,7 +9,7 @@
 import json
 import logging
 import time
-from collections.abc import Mapping
+from collections.abc import Mapping, Sequence
 from pathlib import Path
 
 from kraken.std.util.daemon_controller import DaemonController
@@ -24,7 +24,9 @@
 inject_auth_addon_file = Path(__file__).parent / "mitm_addon.py"
 
 
-def start_mitmweb_proxy(auth: Mapping[str, tuple[str, str]], startup_wait_time: float = 3.0) -> tuple[str, Path]:
+def start_mitmweb_proxy(
+    auth: Mapping[str, tuple[str, str]], startup_wait_time: float = 3.0, additional_args: Sequence[str] = ()
+) -> tuple[str, Path]:
     controller = DaemonController("kraken.mitmweb", daemon_state_file)
     started = controller.run(
         command=[
@@ -47,6 +49,7 @@ def start_mitmweb_proxy(auth: Mapping[str, tuple[str, str]], startup_wait_time:
             # context.
             "--set",
             "stream_large_bodies=3m",
+            *additional_args,
         ],
         cwd=Path("~").expanduser(),
         stdout=daemon_log_file,