DEBIAN-CVE-2026-115889

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make...

CVE-2026-115892

Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or...

CVE-2026-115889

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make...

CVE-2026-115893

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19, 48.0.7, and 49.0.4, the Cranelift compiler backend on aarch64 can compile a Wasm brtable instruction with more than approximately 256,000 targets so that it has an incorrect conditional branch target. The branch can then jump to arbitrary...

GHSA-9PVW-HWFG-92H5 Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type

Summary Wasmtime may panic when the host lowers a component model stream or future into a guest, if the host created that stream or future with one payload type and the guest expects a different one. This can happen when an embedder creates a stream or future, passes it through a guest, receives ...

GHSA-897F-G5GM-FMXM Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation

Summary In Wasmtime prior to v43, the Cranelift compiler backend bit-packs its SSA value indices in a way that can result in silent overflow in release builds, and result in incorrect value references in the IR resulting in arbitrary miscompilation. A very large Wasm function body, or one that is...

CVE-2026-115892

A flaw was found in Wasmtime. A malicious WebAssembly guest can cause a Denial of Service DoS by triggering an unhandled host runtime panic. When handling asynchronous streams or futures exchanged between the host and guest, Wasmtime fails to properly validate payload data types upon their return...

CVE-2026-115893

The Wasmtime WebAssembly runtime is vulnerable to a sandbox escape on aarch64 engines using the default Cranelift backend. The issue occurs when processing a br_table instruction containing more than approximately 256,000 targets, causing an incorrect conditional branch target . This allows a use...

EUVD-2026-109188

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19, 48.0.7, and 49.0.4, the Cranelift compiler backend on aarch64 can compile a Wasm brtable instruction with more than approximately 256,000 targets so that it has an incorrect conditional branch target. The branch can then jump to arbitrary...

CVE-2026-115893 Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19, 48.0.7, and 49.0.4, the Cranelift compiler backend on aarch64 can compile a Wasm brtable instruction with more than approximately 256,000 targets so that it has an incorrect conditional branch target. The branch can then jump to arbitrary...

CVE-2026-115892

The Wasmtime runtime is vulnerable to a Denial of Service (DoS) due to a flaw in how it handles asynchronous streams or futures exchanged between the host and the guest. Specifically, versions 46.0.0 through 48.0.7 and 49.0.4 fail to perform required payload-type checks when values return through...

EUVD-2026-109187

Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or...

CVE-2026-115892 Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type

Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or...

EUVD-2026-109186

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make...

CVE-2026-115889

The Wasmtime runtime is vulnerable to a numeric truncation error (CWE-197) and type confusion (CWE-843) in its Cranelift compiler backend prior to versions 36.0.19 and 43.0.0 . The root cause is a silent overflow occurring during the bit-packing of SSA value indices in release builds when process...

CVE-2026-115889 Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make...

CVE-2026-115389

A flaw was found in Wasmtime. The runtime does not adequately account for host memory allocations when converting guest values through the dynamically-typed Val application programming interface API, bypassing configured resource consumption limits. A malicious WebAssembly guest can exploit this...

CVE-2026-115386

A flaw was found in Wasmtime. An information disclosure vulnerability exists in the WebAssembly System Interface WASI directory reading implementation, which copies uninitialized structure padding into guest memory. A guest module with access to a preopened directory can exploit this issue by...

CVE-2026-115393

A flaw was found in Wasmtime. Several Store application programming interfaces APIs fail to verify that objects belong to the expected execution engine. If an embedding application mixes objects between different engines, this type confusion can lead to memory corruption, including out-of-bounds...

CVE-2026-115391

A flaw was found in Wasmtime. A malicious guest can cause a Denial of Service DoS on the host by submitting excessively large data buffers to file or HTTP write streams within the WebAssembly System Interface WASI. Because incoming guest writes are buffered in host memory without size limits, thi...