bytecodealliance wasmtime up to 36.0.7/43.0.1/44.0.0 WebAssembly allocation of resources

Summaryinfo

A vulnerability categorized as problematic has been discovered in bytecodealliance wasmtime up to 36.0.7/43.0.1/44.0.0. Impacted is an unknown function of the component WebAssembly Module. Such manipulation leads to allocation of resources. This vulnerability is documented as CVE-2026-44216. The attack can be executed remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in bytecodealliance wasmtime up to 36.0.7/43.0.1/44.0.0. It has been rated as problematic. Affected by this issue is an unknown functionality of the component WebAssembly Module. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. CVE summarizes:

Wasmtime is a runtime for WebAssembly. From 30.0.0 to 36.0.8, 43.0.2, and 44.0.1, Wasmtime's allocation logic for a WebAssembly table contained checked arithmetic which panicked on overflow. This overflow is possible to trigger, and thus panic, when a table with an extremely large size is allocated. This is possible with the WebAssembly memory64 proposal where tables can have sizes in the 64-bit range as opposed to the previous 32-bit range which would not overflow. The panic happens when attempting to create a very large table, such as when instantiating a WebAssembly module or component. This vulnerability is fixed in 36.0.8, 43.0.2, and 44.0.1.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-44216 since 05/05/2026. The exploitation is known to be easy. The attack may be launched remotely. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 36.0.8 or 43.0.2 eliminates this vulnerability.

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Productinfo

Vendor

• bytecodealliance

Name

• wasmtime

Version

• 36.0.0
• 36.0.1
• 36.0.2
• 36.0.3
• 36.0.4
• 36.0.5
• 36.0.6
• 36.0.7
• 43.0.0
• 43.0.1
• 44.0

Website

• Product: https://github.com/bytecodealliance/wasmtime/

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