1559 matches found
Two Critical Wasmtime Flaws Could Let Malicious WebAssembly Modules Escape Sandboxes
Two critical flaws in Wasmtime, a WebAssembly runtime that can be built into other software, could allow a malicious WebAssembly module to escape the sandbox intended to contain it, the project's maintainers say. An attacker would first need a vulnerable Wasmtime build to compile a module they...
UBUNTU-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...
UBUNTU-CVE-2026-115382
Wasmtime 46.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains a denial-of-service vulnerability in its wasi:http implementation that allows guests to panic the host. Guests can specify a zero between-bytes-timeout request option, which is forwarded directly to a Tokio API that panics, crashing...
UBUNTU-CVE-2026-115384
Wasmtime 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains a stack buffer overflow vulnerability that allows malicious guests to write 16KB to the native stack via unvalidated async callback result types. Attackers can supply components with mistyped component-model-async callback functions ...
UBUNTU-CVE-2026-115380
Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 contains a denial of service vulnerability in the wasmtime-wasi WASI preview 0 polloneoff adapter, which performs On host work per subscription without consuming or checking fuel. Malicious guest modules can pass many...
UBUNTU-CVE-2026-115381
Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 contains an unbounded memory allocation in the wasmtime-wasi WASIp2 write-zeroes method of SinkOutputStream, the default stream used when stdout/stderr are not configured. A malicious WebAssembly guest can request huge...
UBUNTU-CVE-2026-115385
Wasmtime 46.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains a denial of service vulnerability in the wasmtime-wasi WASIp3 implementation that allows guests to abort the Unix host process. Guests with mutable preopened directory access can call set-times or set-times-at with negative seconds...
UBUNTU-CVE-2026-115386
Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 contains an information disclosure vulnerability in the WASIp1 fdreaddir implementation that copies uninitialized struct padding into guest memory. Guests with a preopened directory can list entries to receive three bytes of...
UBUNTU-CVE-2026-115388
wasmtime-wasi-http in Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not enforce the wasi:io/streams check-write allowance for WASIp2 outgoing HTTP bodies, so oversized writes succeed instead of trapping. A malicious guest can pass large buffers to write on...
UBUNTU-CVE-2026-115387
Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 contains a denial of service vulnerability in wasmtime-wasi that allows guest WASI programs to panic the host via overflowing filesystem timestamps. Attackers can pass atim or mtim values whose sub-second field overflows the...
UBUNTU-CVE-2026-115392
Wasmtime before 24.0.13, 25.0.0 before 36.0.14, 37.0.0 before 46.0.3, and 47.0.0 before 47.0.4 allows a filesystem sandbox escape in wasmtime-wasi because its cap-std dependency mishandles symlinks with trailing slashes on macOS and Linux kernels lacking openat2. A guest with write access to any...
UBUNTU-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...
UBUNTU-CVE-2026-115379
Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains a missing GC rooting vulnerability that leaves references live across trycall unrooted when compiling Wasm modules. Attackers can supply Wasm modules whose callee triggers garbage collection, leaving stale or dangling references that...
UBUNTU-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...
UBUNTU-CVE-2026-115383
Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains an improper validation vulnerability that accepts components whose core modules import WebAssembly tags with a subtype of the original type. Malicious guests can mis-type exception object payloads to corrupt the GC heap, causing...
UBUNTU-CVE-2026-115389
Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not adequately account for host allocations when lifting guest values through the dynamically-typed Val API, bypassing the hostcall fuel limit. A malicious WebAssembly guest can return crafted values that allocate at lea...
UBUNTU-CVE-2026-115393
Wasmtime before 24.0.12, 25.0.0 before 36.0.13, 37.0.0 before 46.0.2, and 47.0.0 before 47.0.3 contains a type confusion vulnerability because several Store APIs fail to validate that objects belong to the Store's Engine. Embedders mixing objects between Engines via Instance::new,...
UBUNTU-CVE-2026-115391
Wasmtime 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4 contains an uncontrolled resource allocation vulnerability in its WASIp3 implementation that buffers guest-specified-length writes on the host without limit. Malicious guests can offer large buffers to WASIp3 file or HTTP write streams, causi...
UBUNTU-CVE-2026-115390
Wasmtime 47.0.0 before 48.0.3 and 49.0.0 before 49.0.1 contains a fuel accounting flaw in Cranelift-compiled callref and trytable catch paths. Malicious guests can reset consumed fuel after calls to run exponentially long on linear fuel, evading timeouts and periodic yields for denial of service...
