{"id":"CVE-2026-121441","aliases":["EUVD-2026-115863","GHSA-9ccp-mgf6-9v48","GHSA-r8xh-cgf7-392j","RUSTSEC-2026-0376"],"status":"published","title":"Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 wasi-http Request Smuggling","description":"Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 contains a request smuggling vulnerability in wasi-http that allows guests to set multiple conflicting content-length headers. Malicious guests can make the host send HTTP requests with conflicting content-length values to smuggle requests through servers or intermediaries that do not reject them.","severity":{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00224,"percentile":0.13184,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-444"],"published":"2026-10-19T12:00:00Z","modified":"2026-11-04T02:47:30Z","fixes":[{"ecosystem":"crates.io","package":"wasmtime-wasi-http","fixed_in":["36.0.19","48.0.7","49.0.4"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"crates.io","package":"wasmtime-wasi-http","ranges":[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"36.0.19"},{"introduced":"37.0.0"},{"fixed":"48.0.7"},{"introduced":"49.0.0"},{"fixed":"49.0.4"}]}]}],"products":[{"vendor":"bytecodealliance","product":"wasmtime"}],"references":[{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-r8xh-cgf7-392j","tags":["vendor-advisory","advisory"]},{"url":"https://www.vulncheck.com/advisories/wasmtime-before-36.0.19-37.0.0-before-48.0.7-and-49.0.0-before-49.0.4-wasi-http-request-smuggling","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121441","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-9ccp-mgf6-9v48"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/121xxx/CVE-2026-121441.json","tags":["advisory"]},{"url":"https://crates.io/crates/wasmtime-wasi-http","tags":["package"]},{"url":"https://rustsec.org/advisories/RUSTSEC-2026-0376.html","tags":["advisory"]},{"url":"https://github.com/bytecodealliance/wasmtime/pull/14824","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2026-121441","title":"Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 wasi-http Request Smuggling","description":"Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 contains a request smuggling vulnerability in wasi-http that allows guests to set multiple conflicting content-length headers. Malicious guests can make the host send HTTP requests with conflicting content-length values to smuggle requests through servers or intermediaries that do not reject them.","status":"published","published":"2026-11-03T14:28:31.931Z","modified":"2026-11-03T16:57:45.823Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna"},{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-444"],"updated_at":"2026-11-03T17:29:02.209656Z"}],"euvd":[{"id":"EUVD-2026-115863","description":"Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 contains a request smuggling vulnerability in wasi-http that allows guests to set multiple conflicting content-length headers. Malicious guests can make the host send HTTP requests with conflicting content-length values to smuggle requests through servers or intermediaries that do not reject them.","status":"published","published":"2026-11-03T14:28:31Z","modified":"2026-11-03T16:57:45Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-03T18:19:04.249016Z"}],"ghsa":[{"id":"GHSA-9ccp-mgf6-9v48","title":"Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 contains a request...","description":"Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 contains a request smuggling vulnerability in wasi-http that allows guests to set multiple conflicting content-length headers. Malicious guests can make the host send HTTP requests with conflicting content-length values to smuggle requests through servers or intermediaries that do not reject them.","status":"published","published":"2026-11-03T15:32:18Z","modified":"2026-11-03T15:32:24Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"low"},{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium"}],"cwes":["CWE-444"],"updated_at":"2026-11-03T17:59:57.372966Z"}],"nvd":[{"id":"CVE-2026-121441","description":"Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 contains a request smuggling vulnerability in wasi-http that allows guests to set multiple conflicting content-length headers. Malicious guests can make the host send HTTP requests with conflicting content-length values to smuggle requests through servers or intermediaries that do not reject them.","status":"published","published":"2026-11-03T15:17:35.927Z","modified":"2026-11-03T17:18:09.783Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"low","assessor":"secondary"}],"cwes":["CWE-444"],"updated_at":"2026-11-03T20:18:19.129968Z"}],"osv":[{"id":"CVE-2026-121441","title":"Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 wasi-http Request Smuggling","description":"Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 contains a request smuggling vulnerability in wasi-http that allows guests to set multiple conflicting content-length headers. Malicious guests can make the host send HTTP requests with conflicting content-length values to smuggle requests through servers or intermediaries that do not reject them.","status":"published","published":"2026-11-03T14:28:31.931Z","modified":"2026-11-05T02:30:26.40283438Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-444"],"updated_at":"2026-11-07T03:08:01.726202Z"},{"id":"RUSTSEC-2026-0376","title":"`wasi-http`: Guests can add conflicting content lengths to messages","description":"This is an entry in the RustSec database for the Wasmtime security advisory\nlocated at\nhttps://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-r8xh-cgf7-392j\nFor more information see the GitHub-hosted security advisory.","status":"published","published":"2026-10-19T12:00:00Z","modified":"2026-11-04T02:55:53.874468619Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"low"}],"updated_at":"2026-11-04T03:25:28.514393Z"}]}}