{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-121439","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","state":"PUBLISHED","assignerShortName":"VulnCheck","dateReserved":"2026-11-03T12:32:14.752Z","datePublished":"2026-11-03T14:28:30.570Z","dateUpdated":"2026-11-03T14:28:30.570Z"},"containers":{"cna":{"providerMetadata":{"orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","shortName":"VulnCheck","dateUpdated":"2026-11-03T14:28:30.570Z"},"datePublic":"2026-10-19T00:00:00.000Z","title":"Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 HTTP Response Splitting via wasi-http","descriptions":[{"lang":"en","value":"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."}],"problemTypes":[{"descriptions":[{"lang":"en","description":"Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","cweId":"CWE-444","type":"CWE"}]}],"affected":[{"vendor":"bytecodealliance","product":"wasmtime","defaultStatus":"unaffected","packageURL":"pkg:cargo/wasmtime-wasi-http","versions":[{"version":"46.0.0","status":"affected","versionType":"semver","lessThan":"48.0.7"},{"version":"48.0.7","status":"unaffected","versionType":"semver"},{"version":"49.0.0","status":"affected","versionType":"semver","lessThan":"49.0.4"},{"version":"49.0.4","status":"unaffected","versionType":"semver"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:*","versionStartIncluding":"46.0.0","versionEndExcluding":"48.0.7"},{"vulnerable":true,"criteria":"cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:*","versionStartIncluding":"49.0.0","versionEndExcluding":"49.0.4"}]}]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"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","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM"}}],"references":[{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-9prg-84vf-g5fc","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-9prg-84vf-g5fc)"},{"name":"VulnCheck Advisory: Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 HTTP Response Splitting via wasi-http","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"}],"x_generator":{"engine":"vulncheck-endgame"}}}}