CVE-2026-115893

critical

Description

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.

References

https://thehackernews.com/2026/10/two-critical-wasmtime-flaws-could-let.html

https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-mghf-wjfp-p5xm

https://github.com/bytecodealliance/wasmtime/releases/tag/v49.0.4

https://github.com/bytecodealliance/wasmtime/releases/tag/v48.0.7

https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.19

https://github.com/bytecodealliance/wasmtime/pull/14826

https://github.com/bytecodealliance/wasmtime/pull/14820

https://github.com/bytecodealliance/wasmtime/pull/14819

https://github.com/bytecodealliance/wasmtime/pull/14818

https://github.com/bytecodealliance/wasmtime/commit/f517bd6e890c7c1291ab9fe05d8cc0c9f11e56aa

https://github.com/bytecodealliance/wasmtime/commit/e61df1b454be9313d61a5f8de07722a421139bbe

https://github.com/bytecodealliance/wasmtime/commit/994549891c8a706cb4f2809f9d17b9f67b31e618

https://github.com/bytecodealliance/wasmtime/commit/222ff3a65dab9aa7011f8c246937751a0bac5abd

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-109188

Details

Source: Mitre, NVD

Published: 2026-10-23

Updated: 2026-10-29

Named Vulnerability: GHSA-mghf-wjfp-p5xm

Risk Information

CVSS v2

Base Score: 9

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 9.9

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Severity: Critical

EPSS

EPSS: 0.0099