PT-2026-31692

Name of the Vulnerable Software and Affected Versions Wasmtime versions 25.0.0 through 36.0.6, 42.0.2, and 43.0.1 Description Wasmtime, a runtime for WebAssembly, has an issue in its Winch compiler backend where the translation of the table.grow operator results in an incorrect type. Specifically...

PT-2026-31693

Name of the Vulnerable Software and Affected Versions Wasmtime versions prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1 Description Wasmtime's implementation of transcoding strings between components has a flaw where the return value of a guest component's realloc function is not validated before the...

wasmtime 缓冲区错误漏洞

Wasmtime is a lightweight WebAssembly runtime open source by the Bytecode Alliance. Versions of Wastime prior to 36.0.7, 42.0.2, and 43.0.1 contained a buffer error vulnerability. This vulnerability stemmed from the pooled allocator using incorrect predicates when resetting virtual memory...

CVE-2026-34941: Out-of-bounds Read

Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a vulnerability where when transcoding a UTF-16 string to the latin1+utf16 component-model encoding it would incorrectly validate the byte length of the input string when performing a bounds chec...

CVE-2026-34944: Uncaught Exception

Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, On x86-64 platforms with SSE3 disabled Wasmtime's compilation of the f64x2.splat WebAssembly instruction with Cranelift may load 8 more bytes than is necessary. When signals-based-traps are disabled this can resul...

CVE-2026-34945: Incorrect Conversion between Numeric Types

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 bug where a 64-bit table, part of the memory64 proposal of WebAssembly, incorrectly translated the table.size instruction. This bug could lead to disclosing data on the...

CVE-2026-34987: Out-of-bounds Read

Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime with its Winch baseline non-default compiler backend may allow properly constructed guest Wasm to access host memory outside of its linear-memory sandbox. This vulnerability requires use of the Winch...

PT-2026-31686

Name of the Vulnerable Software and Affected Versions Wasmtime versions 25.0.0 through 36.0.6, 42.0.2, and 43.0.1 Description Wasmtime's Winch compiler has a flaw in how it handles the table.size instruction with 64-bit tables, part of the WebAssembly memory64 proposal. This can lead to the...

PT-2026-31688

Name of the Vulnerable Software and Affected Versions Wasmtime versions 32.0.0 through 36.0.6, 42.0.2, and 43.0.1 Description Wasmtime's Cranelift compilation backend has a flaw on aarch64 architectures when handling specific heap access patterns. This can lead to incorrect address calculations,...

PT-2026-31689

Wasmtime is a runtime for WebAssembly. In 43.0.0, cloning a wasmtime::Linker is unsound and can result in use-after-free bugs. This bug is not controllable by guest Wasm programs. It can only be triggered by a specific sequence of embedder API calls made by the host. Specifically, the following...

wasmtime 缓冲区错误漏洞

Wasmtime is a lightweight WebAssembly runtime open source by the Bytecode Alliance. Versions prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1 of Wastime contain a buffer error vulnerability. This vulnerability arises from incorrectly verifying the number of code units rather than the byte length when...

PT-2026-31681

Name of the Vulnerable Software and Affected Versions Wasmtime versions prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1 Description Wasmtime's implementation of transcoding strings into the Component Model's utf16 or latin1+utf16 encodings did not properly verify the alignment of reallocated strings...

PT-2026-31690

Name of the Vulnerable Software and Affected Versions Wasmtime versions 25.0.0 through 36.0.6, 42.0.2, and 43.0.1 Description Wasmtime, a runtime for WebAssembly, may allow guest WebAssembly code to access host memory outside of its designated sandbox when using the Winch compiler backend. This...

CVE-2026-34946: Always-Incorrect Control Flow Implementation

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...

CVE-2026-35186: Memory Allocation with Excessive Size Value

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 backend contains a bug where translating the table.grow operator causes the result to be incorrectly typed. For 32-bit tables this means that the result of the operator, internally i...

CVE-2026-35195: Out-of-bounds Write

Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime's implementation of transcoding strings between components contains a bug where the return value of a guest component's realloc is not validated before the host attempts to write through the pointer. This...

wasmtime 缓冲区错误漏洞

Wasmtime is a lightweight WebAssembly runtime open source by the Bytecode Alliance. Versions of Wastime prior to 36.0.7, 42.0.2, and 43.0.1 contained a buffer error vulnerability. This vulnerability stemmed from a flaw in the Winch compiler backend, which could allow guest Wasm access to host...

wasmtime 安全漏洞

Wasmtime is a lightweight WebAssembly runtime open source by the Bytecode Alliance. Versions prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1 of Wastime contain security vulnerabilities. These vulnerabilities arise when using the Val type promotion feature to increase values of component models. If bi...

CVE-2026-34942: Improper Validation of Array Index

Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime's implementation of transcoding strings into the Component Model's utf16 or latin1+utf16 encodings improperly verified the alignment of reallocated strings. This meant that unaligned pointers could be...

CVE-2026-34943: Uncaught Exception

Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a possible panic which can happen when a flags-typed component model value is lifted with the Val type. If bits are set outside of the set of flags the component model specifies that these bits...