What is CVE-2026-115893?

CVE-2026-115893 is a critical-severity vulnerability in Bytecodealliance Wasmtime, classified under CWE-691. CVSS score: 9.9/10. Published 2026-10-23.

How severe is CVE-2026-115893?

Critical severity. CVSS v3 base score is 9.9 out of 10.

Vulnerability in Bytecodealliance Wasmtime

CVE-2026-115893

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19, 48.0.7, and 49.0.4, the Cranelift compiler backend on aarch64 can compile a Wasm br_table instruction with more than approximately 256,000 targets so that it has an incorrect conditional branch target. The branch can then jump to arbitrary other code at a user-controlled offset, allowing a user-controlled Wasm module to escape the sandbox on aarch64 engines using the default Cranelift backend. This issue is fixed in versions 36.0.19, 48.0.7, and 49.0.4.

Published 2026-10-23 · last modified 2026-10-23.

CVSS v3 metric

CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Bytecodealliance Wasmtime — versions < 36.0.19, >= 37.0.0, < 48.0.7, >= 49.0.0, < 49.0.4

Weakness classification (CWE)

CWE-691

References

Frequently asked questions

What is CVE-2026-115893?: CVE-2026-115893 is a critical-severity vulnerability in Bytecodealliance Wasmtime, classified under CWE-691. CVSS score: 9.9/10. Published 2026-10-23.
How severe is CVE-2026-115893?: Critical severity. CVSS v3 base score is 9.9 out of 10.