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 Score
3.7
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-424 |
| Vendor | bytecodealliance |
| Product | wasmtime |
| Published | Nov 3, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None
Affected Versions
bytecodealliance / wasmtime
46.0.0 < 48.0.7 49.0.0 < 49.0.4