Low severity3.7NVD Advisory· Published Nov 3, 2026· Updated Nov 3, 2026

CVE-2026-121440

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.

Affected products

Bytecodealliance/Wasmtimellm-fuzzy
Range: 46.0.0 - 48.0.7, 49.0.0 - 49.0.4

Patches

Vulnerability mechanics

References

github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jxcf-8qw5-5c33nvd
www.vulncheck.com/advisories/wasmtime-46.0.0-before-48.0.7-and-49.0.0-before-49.0.4-forwarded-trailers-header-filter-bypassnvd

News mentions

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cvss	0.240
epss	0.000
exploit	0.000
kev	0.000
patch	0.000
ransomware	0.000