{"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-2026-121439","cwes":["CWE-444"],"description":"Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 contains a response splitting vulnerability in wasi-http p3 that allows guests to set unvalidated content-length headers. Malicious wasip3 guests can splice an existing body into a new response with an incorrect content-length to perform response splitting or injection attacks.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":6.9,"severity":"medium","source":"CNA: VulnCheck","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0"},{"score":5.3,"severity":"medium","source":"CNA: VulnCheck","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"}],"modifiedAt":1793716110570,"publishedAt":1793716110570,"references":[{"source":"CNA: VulnCheck","tags":["vendor-advisory"],"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-9prg-84vf-g5fc"},{"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-http-response-splitting-via-wasi-http"}],"remediation":[],"revision":"12349e38a7ae297276134278e10453acf4e9ce7642b4bca82253d4ae20c5488b","sources":[{"modifiedAt":1793716110570,"name":"CNA: VulnCheck","retrievedAt":1793718591563,"url":"https://www.cve.org/CVERecord?id=CVE-2026-121439"}],"ssvc":null,"status":"published","title":"Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 HTTP Response Splitting via wasi-http","updatedAt":1793718591563}