CVE-2026-121440

Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 Forwarded Trailers Header Filter Bypass

CVSS 4.0 6.3 MEDIUMCVSS 3.1 3.7 LOWEUVD CVSS 4.0 6.3 CVSS 4.0 · [email protected] · Secondary 6.3 MEDIUMCVSS 3.1 · [email protected] · Secondary 3.7 LOWCVSS_V3 Fixed by wasmtime-wasi-http 48.0.7 Fixed by wasmtime-wasi-http 49.0.4KEV status unknown

Original advisory

cve-program · CVE-2026-121440

Published

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.

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euvd · EUVD-2026-115862

Published

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nvd · CVE-2026-121440

Published

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osv · RUSTSEC-2026-0377

Published

This is an entry in the RustSec database for the Wasmtime security advisory located at https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jxcf-8qw5-5c33 For more information see the GitHub-hosted security advisory.

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Affected versions, risk and source history

Exploitation and risk

Source status

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Risk history

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Advisory history

11 saved versions

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14 Nov 2026 07:02:02 UTC