{"api_version":"1","generated_at":"2026-07-23T19:19:51+00:00","cve":"CVE-2020-26281","urls":{"html":"https://cve.report/CVE-2020-26281","api":"https://cve.report/api/cve/CVE-2020-26281.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2020-26281","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2020-26281"},"summary":{"title":"CVE-2020-26281","description":"async-h1 is an asynchronous HTTP/1.1 parser for Rust (crates.io). There is a request smuggling vulnerability in async-h1 before version 2.3.0. This vulnerability affects any webserver that uses async-h1 behind a reverse proxy, including all such Tide applications. If 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. One 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. Another 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. This has been addressed in async-h1 2.3.0 and previous versions have been yanked.","state":"PUBLIC","assigner":"security-advisories@github.com","published_at":"2020-12-21 22:15:00","updated_at":"2021-02-16 17:16:00"},"problem_types":["CWE-444"],"metrics":[],"references":[{"url":"https://github.com/http-rs/async-h1/security/advisories/GHSA-4vr9-8cjf-vf9c","name":"https://github.com/http-rs/async-h1/security/advisories/GHSA-4vr9-8cjf-vf9c","refsource":"CONFIRM","tags":["Third Party Advisory"],"title":"Async-h1 request smuggling possible with long unread bodies · Advisory · http-rs/async-h1 · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"0"},{"url":"https://github.com/http-rs/async-h1/releases/tag/v2.3.0","name":"https://github.com/http-rs/async-h1/releases/tag/v2.3.0","refsource":"MISC","tags":["Release Notes","Third Party Advisory"],"title":"Release v2.3.0 · http-rs/async-h1 · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"200"},{"url":"https://www.cve.org/CVERecord?id=CVE-2020-26281","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-26281","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2020","cve_id":"26281","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"rust-lang","cpe5":"async-h1","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"rust","cpe12":"*","cpe13":"*"},{"cve_year":"2020","cve_id":"26281","vulnerable":"1","versionEndIncluding":"1","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"rust-lang","cpe5":"async-h1","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"rust","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"CVE_data_meta":{"ASSIGNER":"security-advisories@github.com","ID":"CVE-2020-26281","STATE":"PUBLIC","TITLE":"request smuggling in async-h1"},"affects":{"vendor":{"vendor_data":[{"product":{"product_data":[{"product_name":"async-h1","version":{"version_data":[{"version_value":"< 2.3.0"}]}}]},"vendor_name":"http-rs"}]}},"data_format":"MITRE","data_type":"CVE","data_version":"4.0","description":{"description_data":[{"lang":"eng","value":"async-h1 is an asynchronous HTTP/1.1 parser for Rust (crates.io). 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Another 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. This has been addressed in async-h1 2.3.0 and previous versions have been yanked."}]},"impact":{"cvss":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.8,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N","version":"3.1"}},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')"}]}]},"references":{"reference_data":[{"name":"https://github.com/http-rs/async-h1/security/advisories/GHSA-4vr9-8cjf-vf9c","refsource":"CONFIRM","url":"https://github.com/http-rs/async-h1/security/advisories/GHSA-4vr9-8cjf-vf9c"},{"name":"https://github.com/http-rs/async-h1/releases/tag/v2.3.0","refsource":"MISC","url":"https://github.com/http-rs/async-h1/releases/tag/v2.3.0"}]},"source":{"advisory":"GHSA-4vr9-8cjf-vf9c","discovery":"UNKNOWN"}},"nvd":{"publishedDate":"2020-12-21 22:15:00","lastModifiedDate":"2021-02-16 17:16:00","problem_types":["CWE-444"],"metrics":{"baseMetricV3":{"cvssV3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"LOW","integrityImpact":"HIGH","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH"},"exploitabilityScore":2.2,"impactScore":4.7},"baseMetricV2":{"cvssV2":{"version":"2.0","vectorString":"AV:N/AC:M/Au:N/C:P/I:P/A:N","accessVector":"NETWORK","accessComplexity":"MEDIUM","authentication":"NONE","confidentialityImpact":"PARTIAL","integrityImpact":"PARTIAL","availabilityImpact":"NONE","baseScore":5.8},"severity":"MEDIUM","exploitabilityScore":8.6,"impactScore":4.9,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":false}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:rust-lang:async-h1:*:*:*:*:*:rust:*:*","versionEndExcluding":"2.3.0","cpe_name":[]}]}]}},"legacy_mitre":{"record":{"CveYear":"2020","CveId":"26281","Ordinal":"187703","Title":"CVE-2020-26281","CVE":"CVE-2020-26281","Year":"2020"},"notes":[{"CveYear":"2020","CveId":"26281","Ordinal":"1","NoteData":"async-h1 is an asynchronous HTTP/1.1 parser for Rust (crates.io). There is a request smuggling vulnerability in async-h1 before version 2.3.0. This vulnerability affects any webserver that uses async-h1 behind a reverse proxy, including all such Tide applications. If 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. One 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. 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