Integer overflow in Bytecodealliance Wasmtime
CVE-2026-44216
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.
EPSS: 0.003 (24.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Bytecodealliance Wasmtime — versions >= 30.0.0, < 36.0.8, >= 37.0.0, < 43.0.2, 44.0.0
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-44216?
- CVE-2026-44216 is a high-severity vulnerability in Bytecodealliance Wasmtime, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-05-14.
- How severe is CVE-2026-44216?
- High severity. CVSS v3 base score is 7.5 out of 10.