Description
Wasmtime 47.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a memory misalignment flaw in VMContext layout that causes undefined behavior when modules contain an odd number of exception tags. A WebAssembly module with an odd tag count misaligns subsequent host fields in embedders with exceptions enabled, although no exploitation path is currently known.
Published: 2026-10-29
Score: 2.1 Low
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Thu, 29 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 29 Oct 2026 16:15:00 +0000

Type Values Removed Values Added
Description Wasmtime 47.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a memory misalignment flaw in VMContext layout that causes undefined behavior when modules contain an odd number of exception tags. A WebAssembly module with an odd tag count misaligns subsequent host fields in embedders with exceptions enabled, although no exploitation path is currently known.
Title Wasmtime 47.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Misaligned VMContext via Exception Tags
First Time appeared Bytecodealliance
Bytecodealliance wasmtime
Weaknesses CWE-758
CPEs cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:*
Vendors & Products Bytecodealliance
Bytecodealliance wasmtime
References
Metrics cvssV3_1

{'score': 2.6, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N'}

cvssV4_0

{'score': 2.1, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N'}


Subscriptions

Bytecodealliance Wasmtime
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-29T17:14:39.514Z

Reserved: 2026-10-29T14:26:15.522Z

Link: CVE-2026-119133

cve-icon Vulnrichment

Updated: 2026-10-29T16:16:14.108Z

cve-icon NVD

Status : Deferred

Published: 2026-10-29T16:18:06.423

Modified: 2026-10-29T18:17:30.473

Link: CVE-2026-119133

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-29T19:45:11Z

Weaknesses
  • CWE-758

    Reliance on Undefined, Unspecified, or Implementation-Defined Behavior