CVE-2026-121439: medium-severity vulnerability in bytecodealliance wasmtime
Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 HTTP Response Splitting via wasi-http
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.9epss 0.2%
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.
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
Affected products
bytecodealliance · wasmtimeRelated CVEs — bytecodealliance wasmtime
In the same product, most dangerous first.
CVE-2022-31104MEDIUMMiscompilation of `i8x16.swizzle` and `select` with v128 inputs in WasmtimeEPSS 1.8%CVE-2023-26489CRITICALGuest-controlled out-of-bounds read/write on x86_64 in wasmtimeEPSS 1.3%CVE-2022-31146MEDIUMUse After Free in WasmtimeEPSS 1.3%CVE-2022-24791HIGHUse after free in WasmtimeEPSS 1.2%CVE-2026-115893CRITICALWasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instructionEPSS 1.0%CVE-2022-39393HIGHWasmtime vulnerable to data leakage between instances in the pooling allocatorEPSS 0.9%