Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-64847— AnyIO process-pool workers can block indefinitely on undrained stderr

Quick assessment

Affected
agronholm anyio
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

AnyIO 是一个高层级的异步并发与网络框架，运行在 Trio 或 asyncio 之上。在 4.14.2 版本之前，AnyIO 启动进程池工作进程时，会将标准错误流（stderr）连接到一个管道，但该管道从未被父进程读取（drain），尽管文档中描述的行为是将所有三个标准流（stdin/stdout/stderr）重定向。如果工作进程中的代码向 写入足够多且受攻击者影响的数据，可能会填满该管道，导致进程在返回标准输出协议响应之前被阻塞，从而使等待中的进程池调用无限期挂起。运行不可信或存在缺陷的工作代码、且该代码能

CVSS 6.8 · Medium EPSS 0.16% · P5

Possible ATT&CK Techniques 1 AI

T1293

Affected Version Matrix 1

VendorProduct Version RangeStatus
agronholm anyio < 4.14.2 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-64847

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
AnyIO process-pool workers can block indefinitely on undrained stderr
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
不加限制或调节的资源分配
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
agronholm anyio < 4.14.2 -

II. Public POCs for CVE-2026-64847

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-64847

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-64847 (1)

Other References for CVE-2026-64847 (2)

IV. Related Vulnerabilities

Same product: anyio
Same vendor: agronholm
Same weakness: CWE-770