CVE-2026-34983

A flaw was found in Wasmtime, a runtime for WebAssembly. This vulnerability allows for a use-after-free condition when a host application incorrectly clones and then drops a wasmtime::Linker instance before its cloned counterpart is used. This can lead to unpredictable program behavior and...

CVE-2026-34987

A flaw was found in Wasmtime, a runtime for WebAssembly. When using its non-default Winch compiler backend, a properly constructed guest WebAssembly Wasm module can exploit an incorrect assumption in how memory offsets are handled. This allows the guest Wasm to access host memory outside its...

auto-wasi (=0.1.0), candid-extractor (>=0.1.0 <=0.1.2) +105 more potentially affected by CVE-2026-35195 via wasmtime (>=0.10.0 <=1.0.2)

wasmtime CARGO version =0.10.0, =0.1.0, =0.1.0, =0.1.0, =0.1.1, =0.5.3-0, =0.4.0, =0.4.0, =0.0.0, =0.5.0, =0.0.1-alpha, =0.40.1, =0.45.0, =0.1.0, =0.3.0 and more Source cves: CVE-2026-35195 Source advisory: OSV:GHSA-394W-HWHG-8VGM...

EUVD-2026-21039

Wasmtime has out-of-bounds write or crash when transcoding component model strings...

GHSA-394W-HWHG-8VGM Wasmtime has out-of-bounds write or crash when transcoding component model strings

Impact 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 enables a guest to cause the host to write arbitrary transcoded string bytes...

Wasmtime has out-of-bounds write or crash when transcoding component model strings

Impact 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 enables a guest to cause the host to write arbitrary transcoded string bytes...

EUVD-2026-21033

Wasmtime has data leakage between pooling allocator instances...

Wasmtime has data leakage between pooling allocator instances

Impact Wasmtime's implementation of its pooling allocator contains a bug where in certain configurations the contents of linear memory can be leaked from one instance to the next. The implementation of resetting the virtual memory permissions for linear memory used the wrong predicate to determin...

GHSA-6WGR-89RJ-399P Wasmtime has data leakage between pooling allocator instances

Impact Wasmtime's implementation of its pooling allocator contains a bug where in certain configurations the contents of linear memory can be leaked from one instance to the next. The implementation of resetting the virtual memory permissions for linear memory used the wrong predicate to determin...

Wasmtime has use-after-free bug after cloning `wasmtime::Linker`

Impact In version 43.0.0 of the wasmtime crate, 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. The typical symptom of this...

EUVD-2026-21029

Wasmtime has use-after-free bug after cloning wasmtime::Linker...

GHSA-HFR4-7C6C-48W2 Wasmtime has use-after-free bug after cloning `wasmtime::Linker`

Impact In version 43.0.0 of the wasmtime crate, 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. The typical symptom of this...

EUVD-2026-21027

Wasmtime: Miscompiled guest heap access enables sandbox escape on aarch64 Cranelift...

Wasmtime: Miscompiled guest heap access enables sandbox escape on aarch64 Cranelift

Impact Wasmtime's Cranelift compilation backend contains a bug on aarch64 when performing a certain shape of heap accesses which means that the wrong address is accessed. When combined with explicit bounds checks a guest WebAssembly module this can create a situation where there are two diverging...

GHSA-JHXM-H53P-JM7W Wasmtime: Miscompiled guest heap access enables sandbox escape on aarch64 Cranelift

Impact Wasmtime's Cranelift compilation backend contains a bug on aarch64 when performing a certain shape of heap accesses which means that the wrong address is accessed. When combined with explicit bounds checks a guest WebAssembly module this can create a situation where there are two diverging...

Wasmtime has host panic when Winch compiler executes `table.fill`

Impact 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 i...

GHSA-Q49F-XG75-M9XW Wasmtime has host panic when Winch compiler executes `table.fill`

Impact 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 i...

EUVD-2026-21025

Wasmtime has host panic when Winch compiler executes table.fill...

EUVD-2026-21024

Wasmtime has host data leakage with 64-bit tables and Winch...

GHSA-M9W2-8782-2946 Wasmtime has host data leakage with 64-bit tables and Winch

Impact 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 host's stack to WebAssembly guests. The host's stack can possibly contain sensitive...