An out-of-bounds heap read could occur in the C response parser while building an error message for a malformed response.
An attacker controlled server, or possibly an accidental response could trigger a DoS in the client.
If unable to upgrade, the Python parser is unaffected and can be used with AIOHTTP_NO_EXTENSIONS=1.
Patch: https://github.com/aio-libs/aiohttp/commit/49f65d54150397892f7bcc4aae887767d51c322d
{
"cwe_ids": [
"CWE-125",
"CWE-400",
"CWE-416"
],
"github_reviewed": true,
"github_reviewed_at": "2026-08-03T20:51:13Z",
"nvd_published_at": null,
"severity": "HIGH"
}