Attacker-controlled input included into multipart/payload headers can be used to modify a request to inject additional headers or similar.
In the unlikely situation that an application is passing user-controlled strings into MultipartWriter.append(headers=...) or Payload.headers, then an attacker may be able to modify the request to inject headers or change the contents of the request.
Sanitise such user input.
Patch: https://github.com/aio-libs/aiohttp/commit/bf88077ebb14f4c29924b8e8904cba20c55c28b8
{
"github_reviewed": true,
"github_reviewed_at": "2026-06-15T20:07:26Z",
"nvd_published_at": null,
"severity": "LOW",
"cwe_ids": [
"CWE-113",
"CWE-93"
]
}