chore(deps): update dependency anyio to v4.14.2 [security]

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
anyio (changelog)	4.12.1 → 4.14.2

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AnyIO process-pool workers can block indefinitely on undrained stderr

CVE-2026-64847 / GHSA-5p39-cfhj-2xmp

More information

Details

Impact

AnyIO starts process-pool workers with stderr connected to a pipe but never drains that pipe. The worker redirects stdin and stdout to /dev/null to protect its protocol, but does not redirect stderr even though the documentation says all three standard streams are redirected. Worker code that writes enough attacker-influenced data to stderr can fill the pipe, block before returning the stdout protocol response, and wedge the awaiting process-pool call.

Anyone who runs untrusted or faulty code that writes too much to stderr is at risk.

Patches

This vulnerability will be patched in v4.14.2.

Workarounds

Closing sys.stderr in the target function should at least prevent the deadlock.

Severity

• CVSS Score: 6.8 / 10 (Medium)
• Vector String: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

• https://github.com/agronholm/anyio/security/advisories/GHSA-5p39-cfhj-2xmp
• https://github.com/agronholm/anyio/pull/1207
• https://github.com/agronholm/anyio/commit/f1b7301c8264b0d2e8d24a5788fd29e93dea4040
• https://github.com/agronholm/anyio
• https://github.com/agronholm/anyio/releases/tag/4.14.2

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

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AnyIO: TLSStream IDNA 2003 host name encoding enables potential TLS certificate spoofing

CVE-2026-63374 / GHSA-82r6-8w77-94w6

More information

Details

Impact

Services using internationalized (non-ASCII) domain names are potentially vulnerable to TLS connections made from AnyIO's connect_tcp() or directly via TLSStream.wrap() where the connection has (through other means) been hijacked and redirected to a malicious server. The attacker would obtain a legitimate certificate using the IDNA 2003 encoded version of the domain name and offer it to the connecting client, making the certificate validate properly on the client's end.

Patches

The vulnerability will be patched in v4.14.2.

Workarounds

Encode host names via the idna package prior to connecting.

Severity

• CVSS Score: 9.3 / 10 (Critical)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

References

• https://github.com/agronholm/anyio/security/advisories/GHSA-82r6-8w77-94w6
• https://github.com/agronholm/anyio/pull/1208
• https://github.com/agronholm/anyio/commit/68f58915f82d9be8109ebbbd8f5d70577d43f2ce
• https://github.com/agronholm/anyio
• https://github.com/agronholm/anyio/releases/tag/4.14.2

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

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Release Notes

agronholm/anyio (anyio)

v4.14.2

Compare Source

• Changed ByteReceiveStream.receive() implementations to raise a ValueError when max_bytes is not a positive integer (#​1191)
• Fixed CapacityLimiter.total_tokens rejecting float("inf") when the limiter was instantiated outside of an event loop. The adapter setter checked for infinity by identity (value is math.inf), so only the exact math.inf singleton was accepted, while every backend setter (using math.isinf()) accepts any positive infinity (#​1189; PR by @​greymoth-jp).
• Fixed to_process.run_sync() deadlocking when the worker function writes enough data to sys.stderr to fill the (undrained) pipe buffer. The worker process now redirects sys.stderr to os.devnull as well, matching the documented behavior
• Fixed TLSStream.wrap() matching an internationalized (unicode) host name against the peer certificate using IDNA 2003 (via the standard library) instead of IDNA 2008, which could cause the host name to be matched against the wrong certificate (#​1208)
• Fixed anyio.open_process() (and run_process()) ignoring the extra_groups argument, as it mistakenly passed the value of the group argument instead (#​1209)
• Fixed CapacityLimiter.acquire_nowait() and CapacityLimiter.acquire_nowait_on_behalf_of() raising trio.WouldBlock instead of anyio.WouldBlock on the trio backend when there are no tokens available (#​1218)
• Fixed CapacityLimiter on the asyncio backend over-granting tokens (borrowed_tokens exceeding total_tokens and available_tokens going negative) when a non-blocking acquire was made in the window between a token being released and the notified waiter resuming. The freed token is now reserved for the woken waiter right away, so the non-blocking acquire correctly raises WouldBlock (#​1170; PR by @​gaoflow)
• Fixed unnecessary CPU spin when delivering cancellation from CancelScope on asyncio under certain conditions, including improper cancel scope nesting (#​1111)

v4.14.1

Compare Source

• Fixed teardown of higher-scoped async fixtures failing on asyncio with RuntimeError: Attempted to exit cancel scope in a different task than it was entered in when an async test raise an outcome exception (e.g., pytest.skip(), pytest.xfail(), or pytest.fail()) (#​1179; PR by @​EmmanuelNiyonshuti)
• Fixed CapacityLimiter.total_tokens rejecting a value of 0 when the limiter was instantiated outside of an event loop, contradicting the documented behavior of allowing 0 total tokens (#​1183; PR by @​nyxst4ck)

v4.14.0

Compare Source

• Added support for Python 3.15

• Added an asynchronous implementation of the itertools module (#​998; PR by @​11kkw)

• Added the local_port parameter to connect_tcp() to allow binding to a specific local port before connecting (#​1067; PR by @​nullwiz)

• Added support for custom capacity limiters in async path and file I/O functions and classes

• Added the create_task() task group method for easier asyncio migration (returns a TaskHandle) (#​1098)

• Changed TaskGroup.start_soon() to return a TaskHandle

• Added an option for TaskGroup.start() to return a TaskHandle (which then contains the start value in the start_value property)

• Added the cancel() convenience method to TaskGroup as a shortcut for cancelling the task group's cancel scope

• Improved the error message when a known backend is not installed to suggest the install command (#​1115; PR by @​EmmanuelNiyonshuti)

• Improved anyio.Path to preserve subclass types by returning Self in methods that return path objects (#​1130; PR by @​EmmanuelNiyonshuti)

• Changed the parameter type annotation in anyio.Path.write_bytes() to accept any ReadableBuffer, thus allowing it to accept bytearray and memoryview to match pathlib.Path.write_bytes() (#​1135; PR by @​SAY-5)

• Changed several type annotations to only accept callables returning coroutine-like objects instead of arbitrary awaitables:

  • TaskGroup.start_soon()
  • TaskGroup.start()
  • anyio.from_thread.run()

  This reverts an earlier change from v3.7.0 which was made in error. (#​1153)

• Changed anyio.run to support callables returning arbitrary awaitables at runtime on all backends. Previously, this only worked on asyncio (#​1171; PR by @​gschaffner)

• Changed several classes (and their subclasses) to have __slots__ (with __weakref__):

  • anyio.CancelScope
  • anyio.CapacityLimiter
  • anyio.Condition
  • anyio.Event
  • anyio.Lock
  • anyio.ResourceGuard
  • anyio.Semaphore

• Fixed cancellation exception escaping a cancel scope when triggered via check_cancelled() in a worker thread (#​1113)

• Fixed TaskGroup raising AttributeError instead of a clear error when entered more than once (#​1109; PR by @​bahtya)

• Fixed lost type information when passing arguments to lru_cache (#​1104; PR by @​Graeme22)

• Fixed test resumption after KeyboardInterrupt in async generator fixtures on the asyncio backend (#​1060; PR by @​EmmanuelNiyonshuti)

• Fixed import of __main__ in to_process workers when entrypoint script doesn't end in .py, such as when using console_script entrypoints. (#​1027; PR by @​tapetersen)

• Fixed SocketListener.from_socket() returning a TCP listener for AF_UNIX listening sockets, causing accept() to fail with ENOTSUP (#​1132; PR by @​kudato)

• Fixed UDPSocket.aclose() and ConnectedUDPSocket.aclose() on asyncio returning before the underlying socket FD was actually released (#​1147; PR by @​matias-arrelid)

• Fixed trio backend test runner hanging indefinitely instead of raising an error when dynamically accessing an async fixture via request.getfixturevalue (#​1148; PR by @​EmmanuelNiyonshuti)

• Fixed cancelling tasks started through a BlockingPortal after the portal has been stopped (#​1013; PR by @​puneetdixit200)

• Fixed backend_options being ignored when running the Trio backend via anyio.run(); the options are now passed as keyword arguments to trio.run() again, as documented (a regression from AnyIO 3) (#​1161; PR by @​Zac-HD)

• Fixed asyncio Lock and Semaphore deadlocks caused by cancelled waiters left queued during release (#​1145; PR by @​rasmusfaber, @​x42005e1f and @​agronholm)

v4.13.0

Compare Source

• Dropped support for Python 3.9
• Added a ttl parameter to the anyio.functools.lru_cache wrapper (#​1073; PR by @​Graeme22)
• Widened the type annotations of file I/O streams to accept IO[bytes] instead of just BinaryIO (#​1078)
• Fixed anyio.Path not being compatible with Python 3.15 due to the removal of pathlib.Path.is_reserved() and the addition of pathlib.Path.__vfspath__() (#​1061; PR by @​veeceey)
• Fixed the BrokenResourceError raised by the asyncio SocketStream not having the original exception as its cause (#​1055; PR by @​veeceey)
• Fixed the TypeError raised when using "func" as a parameter name in pytest.mark.parametrize when using the pytest plugin (#​1068; PR by @​JohnnyDeuss)
• Fixed the pytest plugin not running tests that had the anyio marker added programmatically via pytest_collection_modifyitems (#​422; PR by @​chbndrhnns)
• Fixed cancellation exceptions leaking from a CancelScope on asyncio when they are contained in an exception group alongside non-cancellation exceptions (#​1091; PR by @​gschaffner)
• Fixed Condition.wait() not passing on a notification when the task is cancelled but already received a notification
• Fixed inverted condition in the process pool shutdown phase which would cause still-running pooled processes not to be terminated (#​1074; PR by @​bysiber)

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