{"id":"GHSA-4vr9-8cjf-vf9c","summary":"Async-h1 request smuggling possible with long unread bodies","details":"### Impact\nThis vulnerability affects any webserver that uses async-h1 behind a reverse proxy, including all such Tide applications.\n\nIf the server does not read the body of a request which is longer than some buffer length, async-h1 will attempt to read a subsequent request from the body content starting at that offset into the body.\n\nOne way to exploit this vulnerability would be for an adversary to craft a request such that the body contains a request that would not be noticed by a reverse proxy, allowing it to forge forwarded/x-forwarded headers. If an application trusted the authenticity of these headers, it could be misled by the smuggled request.\n\nAnother potential concern with this vulnerability is that if a reverse proxy is sending multiple http clients' requests along the same keep-alive connection, it would be possible for the smuggled request to specify a long content and capture another user's request in its body. This content could be captured in a post request to an endpoint that allows the content to be subsequently retrieved by the adversary.\n\n\n### Patches\nThis has been addressed in async-h1 2.3.0 and previous versions have been yanked.\n\n### Workarounds\nnone\n\n### References\nhttps://github.com/http-rs/async-h1/releases/tag/v2.3.0\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [async-h1](https://github.com/http-rs/async-h1)\n* Contact a core team member on [zulip](https://http-rs.zulip-chat.com) or [discord](https://discord.gg/x2gKzst)","aliases":["CVE-2020-26281","CVE-2020-36202","GHSA-c8rq-crxj-mj9m","RUSTSEC-2020-0093"],"modified":"2026-09-10T03:49:08.929331849Z","published":"2021-10-12T16:00:37Z","database_specific":{"nvd_published_at":"2020-12-21T22:15:00Z","cwe_ids":["CWE-444"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2021-10-08T22:14:28Z"},"references":[{"type":"WEB","url":"https://github.com/http-rs/async-h1/security/advisories/GHSA-4vr9-8cjf-vf9c"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-26281"},{"type":"PACKAGE","url":"https://github.com/http-rs/async-h1"},{"type":"WEB","url":"https://github.com/http-rs/async-h1/releases/tag/v2.3.0"},{"type":"WEB","url":"https://rustsec.org/advisories/RUSTSEC-2020-0093.html"}],"affected":[{"package":{"name":"async-h1","ecosystem":"crates.io","purl":"pkg:cargo/async-h1"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.3.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/10/GHSA-4vr9-8cjf-vf9c/GHSA-4vr9-8cjf-vf9c.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N"}]}