PT-2026-121564

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 fd readdir implementation that copies uninitialized struct padding into guest memory. Guests with a preopened directory can list entries to receive three bytes of...

PT-2026-121567

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...

Bytecode Alliance wasmtime input validation error vulnerability

The Bytecode Alliance WasmTime versions prior to 46.0.0 through 48.0.4 and 49.0.0 through 49.0.2 contain an input validation error vulnerability. This vulnerability arises because the Wasi: HTTP implementation allows a guest to set the “between-bytes-timeout” request option to 0 and then directly...

Bytecode Alliance wasmtime numeric error vulnerability

Bytecode Alliance: Versions prior to 36.0.16, versions 37.0.0 through 48.0.3, and versions 49.0.0 through 49.0.1 contain a numerical error vulnerability. This vulnerability arises when wasmtime-wasi processes filesystem timestamps; the subsecond field of the atim or mtim value overflows into the...

PT-2026-121565

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...

PT-2026-121559

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...

PT-2026-121562

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 ...

PT-2026-121570

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...

PT-2026-121561

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...

Bytecode Alliance wasmtime resource management error vulnerability

Bytecode Alliance versions prior to 36.0.16, 37.0.0 through 48.0.3, and 49.0.0 through 49.0.1 contain a resource management error vulnerability. This vulnerability stems from waSTM time-wasi-http failing to enforce a write check limit on the WASIp2 outbound HTTP body, thereby allowing excessively...

Vulnerability related to the software supply chain issue in Bytecode Alliance wasmtime

In versions prior to Bytecode Alliance Wasmtime 48.0.4, versions 47.0.0 and versions prior to 49.0.2, versions 49.0.0 contain a software supply chain vulnerability. This vulnerability stems from improper validation of WebAssembly tag subtype imports for core modules. Malicious actors can...

PT-2026-121568

Wasmtime 47.0.0 before 48.0.3 and 49.0.0 before 49.0.1 contains a fuel accounting flaw in Cranelift-compiled call ref and try table 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 servic...

PT-2026-121560

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...

PT-2026-121557

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 try call unrooted when compiling Wasm modules. Attackers can supply Wasm modules whose callee triggers garbage collection, leaving stale or dangling references tha...

PT-2026-121566

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...

Bytecode Alliance wasmtime input validation error vulnerability

In versions prior to Bytecode Alliance Wasmtime 48.0.4, there is an input validation error vulnerability. This vulnerability stems from the failure to validate the type of results returned by asynchronous callbacks, leading to a stack buffer overflow. A malicious visitor can write approximately 1...

PT-2026-121571

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,...

RUSTSEC-2026-0380 Bit-packing in Cranelift compiler causes silent overflow and miscompilation

This is an entry in the RustSec database for the Wasmtime security advisory located at https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-897f-g5gm-fmxm For more information see the GitHub-hosted security advisory...

RUSTSEC-2026-0378 Panic lowering a host-created component model stream into a guest that expects a different payload type

This is an entry in the RustSec database for the Wasmtime security advisory located at https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-9pvw-hwfg-92h5 For more information see the GitHub-hosted security advisory...

Panic lowering a host-created component model stream into a guest that expects a different payload type

This is an entry in the RustSec database for the Wasmtime security advisory located at https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-9pvw-hwfg-92h5 For more information see the GitHub-hosted security advisory...