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.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-770"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64847.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "4.14.2"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "f1b7301c8264b0d2e8d24a5788fd29e93dea4040"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "4.14.2",
"range": [
{
"fixed": "c384f99687c64c59ed8a11c3a0f11a2d57daff71"
}
],
"source": "REFERENCES_TAG"
}
]
}