CVE-2026-34943
Published:April 09, 2026
Updated:August 06, 2026
Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a possible panic which can happen when a flags-typed component model value is lifted with the Val type. If bits are set outside of the set of flags the component model specifies that these bits should be ignored but Wasmtime will panic when this value is lifted. This panic only affects wasmtime's implementation of lifting into Val, not when using the flags! macro. This additionally only affects flags-typed values which are part of a WIT interface. This has the risk of being a guest-controlled panic within the host which Wasmtime considers a DoS vector. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.
Affected Packages
wasmtime (RUST):
Affected version(s) >=0.0.0 <24.0.7Fix Suggestion:
Update to version 24.0.7wasmtime (RUST):
Affected version(s) =43.0.0 <43.0.1Fix Suggestion:
Update to version 43.0.1wasmtime (RUST):
Affected version(s) >=25.0.0 <36.0.7Fix Suggestion:
Update to version 36.0.7wasmtime (RUST):
Affected version(s) >=37.0.0 <42.0.2Fix Suggestion:
Update to version 42.0.2Related Resources (6)
Do you need more information?
Contact UsCVSS v4
Base Score:
5.6
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
PRESENT
Privileges Required
HIGH
User Interaction
ACTIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
4.2
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
HIGH
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Uncaught Exception
EPSS
Base Score:
0.32