CVE-2026-34946— Wasmtime's host panics when Winch compiler executes `table.fill`

Wasmtime's host panics when Winch compiler executes `table.fill`

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 vulnerability where the compilation of the table.fill instruction can result in a host panic. This means that a valid guest can be compiled with Winch, on any architecture, and cause the host to panic. This represents a denial-of-service vulnerability in Wasmtime due to guests being able to trigger a panic. The specific issue is that a historical refactoring changed how compiled code referenced tables within the table.* instructions. This refactoring forgot to update the Winch code paths associated as well, meaning that Winch was using the wrong indexing scheme. Due to the feature support of Winch the only problem that can result is tables being mixed up or nonexistent tables being used, meaning that the guest is limited to panicking the host (using a nonexistent table), or executing spec-incorrect behavior and modifying the wrong table. This vulnerability is fixed in 36.0.7, 42.0.2, and 43.0.1.

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控制流实现总是不正确

wasmtime 安全漏洞

wasmtime是Bytecode Alliance开源的一个轻量级WebAssembly运行时。 Wasmtime 25.0.0至36.0.7之前版本、42.0.2之前版本和43.0.1之前版本存在安全漏洞，该漏洞源于编译table.fill指令可能导致主机恐慌，构成拒绝服务漏洞，具体问题源于历史重构更改了编译代码在table.*指令中引用表的方式，但未更新相关的Winch代码路径，导致Winch使用了错误的索引方案。

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