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GHSA-mghf-wjfp-p5xm

Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction

Source: GitHub Advisory Database (reviewed) Critical CVE-2026-115893

Packages

EcosystemPackageAffectedFixed in
crates.io wasmtime < 36.0.19 36.0.19
crates.io wasmtime >= 37.0.0, < 48.0.7 48.0.7
crates.io wasmtime >= 49.0.0, < 49.0.4 49.0.4

Details

As written in the advisory (Markdown source, shown as plain text).

## Summary When running with the Cranelift compiler backend on an aarch64 target, Wasmtime can compile a Wasm module with more than ~256k targets on one `br_table` instruction in a way that results in an incorrect conditional branch target. This conditional branch could then jump to arbitrary other code (at an user-controlled offset), leading to arbitrary sandbox escapes. ## Impact Any Wasmtime engine running on aarch64 with default settings can be forced to jump to arbitrary code by a user-controlled Wasm module. All versions of Wasmtime/Cranelift that support aarch64, since the initial release of that support in 2020 (before Wasmtime v1.0), are affected. ## Patches Wasmtime v36.0.19, v48.0.7, and v49.0.4 have been released which all fix this issue.

References

External links from the advisory. They lead to third-party sites.