AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, Request.post() does not limit the number of fields in a URL-encoded form body, and inserting many repeated keys into MultiDict takes quadratic time on the event loop. A remote attacker can send a form POST within client_max_size to a handler that calls Request.post() and block the event loop. This issue is fixed in version 3.14.4.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-407"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/128xxx/CVE-2026-128126.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "3.14.4"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "615fec3d4f088f30d2ee72cad760152e92aa1c53"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "8b0100572936df28977b9de8a6cc7e464c0b521e"
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],
"source": "REFERENCES_COMMIT"
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{
"original_tag": "v3.14.4",
"range": [
{
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}
],
"source": "REFERENCES_TAG"
}
]
}