Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction
Impact
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.
Source excerpt · OSVAffected packages
Start with the recorded fix for your release branch. Check your installed version and test compatibility before upgrading. Fixing this advisory does not rule out other vulnerabilities in the release.
| Affected range | Recorded fix |
|---|---|
| Earlier releases before 36.0.19Semantic versions | 36.0.19 |
| From 37.0.0 before 48.0.7Semantic versions | 48.0.7 |
| From 49.0.0 before 49.0.4Semantic versions | 49.0.4 |
Version evidence: OSV · GHSA-mghf-wjfp-p5xm
View original version evidence (0 explicit versions)
Affected products
Vendor version evidence. Product records are separate from automatic dependency matching.
bytecodealliance · GitHub_M
wasmtime
3 ranges
bytecodealliance · GitHub_M
wasmtime
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affected
< 36.0.19
>= 37.0.0, < 48.0.7
>= 49.0.0, < 49.0.4
Other versions: unknown
Original source description
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.
Inside the record
Evidence available
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Original records
CVE-2026-115893View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.
cve.new JSON →Underlying weaknesses
The source’s classification of what caused the vulnerability.
Contributing organizations · 2
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What changed
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