Vulnerability DatabaseCVE-2026-126408
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CVE-2026-126408
Published:November 13, 2026
Updated:November 13, 2026
Wasmtime 47.0.0 before 48.0.8, 49.0.0 before 49.0.5, and 50.0.0 before 50.0.1 contains an insufficient type-check in the TypedFunc embedder API for I31, Option<I31>, and Option<NoneRef> parameter or result types, reaching an unreachable!() path. A malicious guest module exporting a function that uses another anyref-hierarchy type can panic the host embedding, causing denial of service.
Affected Packages
https://github.com/bytecodealliance/wasmtime.git (GITHUB):
Affected version(s) >=v50.0.0-rc.1 <v50.0.1
Fix Suggestion:
Update to version v50.0.1
https://github.com/bytecodealliance/wasmtime.git (GITHUB):
Affected version(s) >=v20.0.0 <v48.0.8 || >=v21.0.0 <v48.0.8 || >=v22.0.0 <v48.0.8 || >=v23.0.0 <v48.0.8 || >=v24.0.0 <v48.0.8 || >=v25.0.0 <v48.0.8 || >=v26.0.0 <v48.0.8 || =v27.0.0 <v48.0.8 || >=v28.0.0 <v48.0.8 || >=v29.0.0 <v48.0.8 || >=v30.0.0 <v48.0.8 || =v31.0.0 <v48.0.8 || >=v32.0.0 <v48.0.8 || >=v33.0.0 <v48.0.8 || >=v34.0.0 <v48.0.8 || =v35.0.0 <v48.0.8 || >=v36.0.0 <v48.0.8 || >=v37.0.0 <v48.0.8 || >=v38.0.1 <v48.0.8 || >=v39.0.0 <v48.0.8 || >=v40.0.0 <v48.0.8 || >=v41.0.0 <v48.0.8 || >=v42.0.0 <v48.0.8 || >=v43.0.0 <v48.0.8 || >=v44.0.0 <v48.0.8 || >=v45.0.0 <v48.0.8 || >=v46.0.0 <v48.0.8 || >=v47.0.0 <v48.0.8 || >=v48.0.0 <v48.0.8
Fix Suggestion:
Update to version v48.0.8
https://github.com/bytecodealliance/wasmtime.git (GITHUB):
Affected version(s) >=v49.0.0-rc.1 <v49.0.5
Fix Suggestion:
Update to version v49.0.5
wasmtime (RUST):
Affected version(s) >=41.0.0 <48.0.8 || >=47.0.0 <48.0.8 || >=28.0.0 <48.0.8 || =35.0.0 <48.0.8 || >=44.0.0 <48.0.8 || >=23.0.0 <48.0.8 || >=20.0.0 <48.0.8 || >=26.0.0 <48.0.8 || >=25.0.0 <48.0.8 || >=36.0.0 <48.0.8 || >=22.0.0 <48.0.8 || =27.0.0 <48.0.8 || >=39.0.0 <48.0.8 || >=21.0.0 <48.0.8 || >=33.0.0 <48.0.8 || >=46.0.0 <48.0.8 || >=43.0.0 <48.0.8 || >=45.0.0 <48.0.8 || >=30.0.0 <48.0.8 || >=42.0.0 <48.0.8 || >=37.0.0 <48.0.8 || >=29.0.0 <48.0.8 || >=34.0.0 <48.0.8 || >=24.0.0 <48.0.8 || >=32.0.0 <48.0.8 || >=38.0.0 <48.0.8 || >=48.0.0 <48.0.8 || =31.0.0 <48.0.8 || >=40.0.0 <48.0.8
Fix Suggestion:
Update to version 48.0.8
wasmtime (RUST):
Affected version(s) >=50.0.0-rc.1 <50.0.1
Fix Suggestion:
Update to version 50.0.1
wasmtime (RUST):
Affected version(s) >=49.0.0-rc.1 <49.0.5
Fix Suggestion:
Update to version 49.0.5
Related Resources (3)
https://nvd.nist.gov/vuln/detail/CVE-2026-126408
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-3982-jqvv-277m
https://www.vulncheck.com/advisories/wasmtime-47.0.0-before-48.0.8-denial-of-service-via-typedfunc-type-check-panic
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CVSS v4
Base Score:
1
Attack Vector
ADJACENT
Attack Complexity
HIGH
Attack Requirements
PRESENT
Privileges Required
HIGH
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
1.8
Attack Vector
ADJACENT
Attack Complexity
HIGH
Privileges Required
HIGH
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Weakness Type (CWE)
Reachable Assertion
CWE-617
EPSS
Base Score:
0.18