{"affected":[{"defaultStatus":"unaffected","ecosystem":"cargo","packageName":"wasmtime-wasi-http","product":"wasmtime","source":"CNA: VulnCheck","vendor":"bytecodealliance","versions":[{"lessThan":"48.0.7","status":"affected","version":"46.0.0","versionType":"semver"},{"status":"unaffected","version":"48.0.7","versionType":"semver"},{"lessThan":"49.0.4","status":"affected","version":"49.0.0","versionType":"semver"},{"status":"unaffected","version":"49.0.4","versionType":"semver"}]}],"cveId":"CVE-2026-121440","cwes":["CWE-424"],"description":"Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 fails to check forwarded trailers against the WasiHttpHooks::is_forbidden_header hook in wasi-http p3. WASIp3 guests can forward a request or response body so its trailers skip embedder-customized forbidden header filtering, undermining header restrictions the embedder intended.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":6.3,"severity":"medium","source":"CNA: VulnCheck","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","version":"4.0"},{"score":3.7,"severity":"low","source":"CNA: VulnCheck","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"}],"modifiedAt":1793716111228,"publishedAt":1793716111228,"references":[{"source":"CNA: VulnCheck","tags":["vendor-advisory"],"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jxcf-8qw5-5c33"},{"source":"CNA: VulnCheck","tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/wasmtime-46.0.0-before-48.0.7-and-49.0.0-before-49.0.4-forwarded-trailers-header-filter-bypass"}],"remediation":[],"revision":"c6bc2573e66dc1da6d98b3be8facd18d65cbe35b61608ef898f5d0740c12fb1e","sources":[{"modifiedAt":1793716111228,"name":"CNA: VulnCheck","retrievedAt":1793718592667,"url":"https://www.cve.org/CVERecord?id=CVE-2026-121440"}],"ssvc":null,"status":"published","title":"Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 Forwarded Trailers Header Filter Bypass","updatedAt":1793718592667}