Affected: Homebrew: aider

### 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.

Affected: CleanStart: airflow-3

CVE-2026-64847 affects multiple packages. AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. See references for individual vulnerability details.

AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. Prior to 4.14.2, AnyIO starts process-pool workers with standard error connected to a pipe that the parent never drains, even though the documented behavior redirects all three standard streams. Worker code that writes enough attacker-influenced data to sys.stderr can fill the pipe and block before returning the standard-output protocol response, causing the awaiting process-pool call to remain blocked indefinitely. Applications that run untrusted or faulty worker code capable of producing substantial standard-error output are affected. This issue is fixed in version 4.14.2.

Affected: PyPI: anyio

### 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.

Affected: PyPI: anyio

### 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.

python-transformers: python-transformers: Arbitrary code execution due to overridden trust_remote_code setting vllm: vLLM: Denial of Service via unbounded video frame processing aiohttp: AIOHTTP: Arbitrary code execution via untrusted input to CookieJar.load() vllm: vLLM: Arbitrary code execution via malicious HuggingFace model vllm: vLLM: Denial of Service via malformed tensor shape in speculative decoding Diffusers: Diffusers: Arbitrary remote code execution via `trust_remote_code` bypass diffusers: Diffusers: Arbitrary Code Execution via malicious model loading diffusers: Diffusers: Arbitrary code execution due to trust_remote_code guard bypass python-pyjwt: PyJWT: Authentication bypass due to forged JSON Web Tokens starlette: Starlette: Security restriction bypass via malformed HTTP Host header vllm: starlette: vLLM: Critical authentication bypass allows unauthorized API access Pillow: Pillow: Memory disclosure or denial of service via crafted McIdas AREA image python-pillow: Pillow: Denial of Service via excessive memory allocation when processing font files vllm: vLLM: Denial of Service via malformed speculative decoding workload starlette: Starlette: request.form() limits silently ignored for application/x-www-form-urlencoded enable DoS python-pillow: Pillow: Denial of Service via crafted BDF font file python-pillow: Pillow: Denial of Service via crafted GD 2.x image file vllm: vLLM: Denial of Service via adversarial regular expression in structured outputs API msgpac…

Affected: Ubuntu:22.04:LTS: python-anyio, Ubuntu:24.04:LTS: python-anyio, Ubuntu:26.04:LTS: python-anyio

AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. Prior to 4.14.2, AnyIO starts process-pool workers with standard error connected to a pipe that the parent never drains, even though the documented behavior redirects all three standard streams. Worker code that writes enough attacker-influenced data to sys.stderr can fill the pipe and block before returning the standard-output protocol response, causing the awaiting process-pool call to remain blocked indefinitely. Applications that run untrusted or faulty worker code capable of producing substantial standard-error output are affected. This issue is fixed in version 4.14.2.