What is CVE-2026-34945?

CVE-2026-34945 is a medium-severity vulnerability in Bytecodealliance Wasmtime, classified under Incorrect Conversion between Numeric Types. CVSS score: 6.5/10. Published 2026-04-09.

How severe is CVE-2026-34945?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Bytecodealliance Wasmtime

CVE-2026-34945

Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's Winch compiler contains a bug where a 64-bit table, part of the memory64 proposal of WebAssembly, incorrectly translated the table.size ins…

EPSS: 0.003 (24.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

Affected products

Bytecodealliance Wasmtime — versions >= 25.0.0, < 36.0.7, >= 37.0.0, < 42.0.2, >= 43.0.0, < 44.0.1

Weakness classification (CWE)

CWE-681 — Incorrect Conversion between Numeric Types

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-34945?: CVE-2026-34945 is a medium-severity vulnerability in Bytecodealliance Wasmtime, classified under Incorrect Conversion between Numeric Types. CVSS score: 6.5/10. Published 2026-04-09.
How severe is CVE-2026-34945?: Medium severity. CVSS v3 base score is 6.5 out of 10.