Threats affecting pkg:cargo/bytecodealliance/wasmtime

CVE-2026-119143 is a denial of service vulnerability in bytecodealliance's wasmtime affecting versions 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3. The flaw allows guest code to cause a host panic by performing out-of-bounds zero-length stream operations, leading to a crash in WASIp3 embedders.

Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a denial of service vulnerability where dropping the Future returned by TypedFunc::call_async can panic the host. When the guest task has not started, cleanup code searches only one location for work items and unwraps the resulting error, crashing embedders that cancel pending calls.

Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a denial of service vulnerability that allows malicious Wasm modules to panic the host because the may_leave flag is not cleared during realloc. Attackers can call into the host from realloc while lowering stream or future results, such as cancelling the active read or re-waiting a waitable-set, crashing the host.

CVE-2026-119140 is a denial of service vulnerability in bytecodealliance's wasmtime affecting versions 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3. It allows malicious components to cause the host to panic by exploiting thread.yield calls in start functions, leading to a crash due to undisposed fiber drops.

CVE-2026-119139 is a reachable assertion vulnerability in bytecodealliance's wasmtime affecting versions 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3. The flaw occurs in component::Func::call, where a leftover assertion rejects guest exports using the async ABI option. An attacker supplying a component with an async-lifted export can cause the host process to crash when that export is invoked.

Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a denial of service vulnerability that allows pending calls to trigger an assertion failure after a trap poisons the Store. Attackers supplying misbehaving guest code can cause a trap and let earlier calls proceed, crashing embedders that continue using the inconsistent Store.

Wasmtime 42.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a stack overflow vulnerability that allows guests to crash the host through recursive type drops. Guests can define a long chain of recursive types so that removing the top-level type triggers unbounded recursive drops, exhausting the host stack.

CVE-2026-119136 affects Wasmtime versions 42.0.0 before 48.0.6 and 49.0.0 before 49.0.3. The vulnerability arises from insufficient checks in the Store component when mixing asynchronous and synchronous WebAssembly calls. This can lead to runtime panics or unsafe cross-thread movement of non-Send host variables when embedders re-enter WebAssembly synchronously from asynchronously called host functions.

CVE-2026-119135 is a vulnerability in bytecodealliance's wasmtime affecting versions 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3. The issue causes a panic (crash) when the host reads a component model stream as a different Rust item type than it was originally created with. This occurs because the host-to-host read path asserts matching TypeIds instead of returning an error, allowing guest code to trigger a crash by returning a host-created StreamReader<U> that the embedder reads as StreamReader<T>.

Wasmtime before 36.0.18, 37.0.0 before 48.0.6, and 49.0.0 before 49.0.3 caps component-model resource handle tables only per component instance and does not charge handle allocations to any ResourceLimiter or StoreLimits. A malicious guest can repeatedly call resource.new and instantiate sub-components to exceed the per-instance cap many times over, causing unbounded host memory growth.

Wasmtime 47.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a memory misalignment flaw in VMContext layout that causes undefined behavior when modules contain an odd number of exception tags. A WebAssembly module with an odd tag count misaligns subsequent host fields in embedders with exceptions enabled, although no exploitation path is currently known.

Wasmtime versions from 49.0.0 up to but not including 49.0.3 contain a denial-of-service vulnerability. This flaw allows a WebAssembly guest to cause the host to panic by transcoding overlapping strings in fused adapters during component-to-component calls. The issue arises when the source and destination strings alias each other, leading to a crash instead of a controlled trap.

CVE-2026-119131 is a denial of service vulnerability in wasmtime versions 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3. The flaw exists in wasmtime-wasi-http where guests can cause the host to crash by sending excessively long request URLs. Specifically, using set-path-with-query with a '?' character after byte 65535 causes an integer overflow of a u16 index in the http crate, triggering a host panic.

Wasmtime before 36.0.18, 37.0.0 before 48.0.6, and 49.0.0 before 49.0.3 does not verify that set-path-with-query values in wasmtime-wasi-http are paths, so absolute-form URLs are written verbatim as the HTTP/1.1 request target while the connection uses the allowed authority. A malicious guest can supply an absolute URL that a forward proxy or gateway at that authority honors, reaching hosts disallowed by embedder filtering policies.

A vulnerability in Wasmtime involves unchecked memory usage when transferring borrowed resources between components. This flaw affects multiple versions prior to fixed releases. The issue could lead to memory safety problems if exploited. Fixed versions are available, and patches have been released.

A vulnerability in Wasmtime involving cross-engine type confusion with host-created struct types that have supertypes. This flaw affects multiple versions of Wasmtime prior to fixed releases. It was addressed in versions 48.0.8, 49.0.5, and 50.0.1.

Wasmtime versions 47.0.0 through 48.0.7, 49.0.0 through 49.0.4, and 50.0.0 are affected by a vulnerability where typed functions with i31 or nullref arguments may panic due to insufficient type-checking. This issue has a low severity impact and does not affect confidentiality or integrity but may cause a denial of service through application panic. Fixed versions are 48.0.8, 49.0.5, and 50.0.1.

A vulnerability in Wasmtime's Cranelift backend on aarch64 allows a conditional branch in a large Wasm br_table instruction to jump to an incorrect target. This can lead to arbitrary code execution and sandbox escapes. The issue affects all Wasmtime versions supporting aarch64 since 2020 before specific patched releases. Fixes are available in Wasmtime versions 36.0.19, 48.0.7, and 49.0.4.

CVE-2026-118688 is a vulnerability in wasmtime-wasi in Wasmtime versions before 36.0.18, 48.0.6, and 49.0.3. It involves the re-appending of a trailing slash to rename source paths, which causes the renameat system call on macOS and FreeBSD hosts to follow directory symbolic links (symlinks). This allows a guest with sandbox write access to rename a relative symlink such as "up/" to move host directories into its sandbox, potentially enabling unauthorized read or write access to host directories.

A stack buffer overflow vulnerability exists in Wasmtime versions 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2. The provided data references Microsoft but does not detail the specific impact or exploitation. No CVSS score or patch information is available in the input.