CVE-2026-115893 is a critical vulnerability in the bytecodealliance wasmtime runtime for WebAssembly on aarch64 platforms using the Cranelift compiler backend. Versions prior to 36.0.19, between 37.0.0 and before 48.0.7, and between 49.0.0 and before 49.0.4 are affected. The flaw allows a user-controlled WebAssembly module to escape the sandbox by exploiting an incorrect conditional branch target when compiling a br_table instruction with more than approximately 256,000 targets. This can lead to arbitrary code execution outside the sandbox. The issue is fixed in versions 36.0.19, 48.0.7, and 49.0.4.
CVE-2026-115892 is a medium severity vulnerability in the Wasmtime runtime for WebAssembly. It involves a type confusion issue where a host-created component-model stream or future can omit a required payload-type check after passing through guest code. This can cause the host to panic when a type-erased value is passed to a guest expecting a different payload type. The issue affects Wasmtime versions from 46.0.0 up to but not including 48.0.7, and from 49.0.0 up to but not including 49.0.4. The vulnerability is fixed in versions 48.0.7 and 49.0.4.
A numeric truncation error in the Cranelift compiler backend of Wasmtime prior to versions 36.0.19 and 43.0.0 can cause silent overflow when compiling large or specially crafted WebAssembly functions. This overflow leads to incorrect intermediate representation references, resulting in arbitrary miscompilation, type confusion, and potentially attacker-controlled effects that may break out of the Wasm sandbox. The issue is fixed in versions 36.0.19 and 43.0.0.
CVE-2026-115393 is a type confusion vulnerability in the bytecodealliance wasmtime project affecting multiple version ranges before specific fixed releases. The flaw arises because certain Store APIs do not validate that objects belong to the Store's Engine, allowing embedders to mix objects between Engines. This can cause trampoline signature mismatches leading to out-of-bounds stack writes, garbage collector heap corruption, or panics.
CVE-2026-115392 is a high-severity vulnerability in the bytecodealliance wasmtime runtime affecting multiple version ranges before specific fixed releases. It allows a filesystem sandbox escape via mishandling of symbolic links with trailing slashes on macOS and Linux kernels lacking openat2 support. This flaw enables a guest with write access to any sandboxed directory to read and write any host-accessible file, and read-only guests to read host files through preexisting symlinks.
Wasmtime versions 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4 contain a vulnerability in the WASIp3 implementation where guest-specified-length writes are buffered without limits. This can lead to excessive memory consumption on the host system, potentially exhausting host memory resources.
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 service.
CVE-2026-115389 is a resource allocation vulnerability in bytecodealliance's wasmtime affecting versions before 36.0.16, between 37.0.0 and before 48.0.3, and between 49.0.0 and before 49.0.1. The issue arises because wasmtime does not properly account for host memory allocations when lifting guest values via the Val API, allowing a malicious WebAssembly guest to allocate significantly more host memory than tracked. This can lead to denial of service due to resource exhaustion. The vulnerability has a low severity rating and no known exploits in the wild. No patch links are provided in the input data.
CVE-2026-115388 is a vulnerability in the wasmtime-wasi-http component of Wasmtime that allows uncontrolled resource consumption. Versions before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 do not enforce the wasi:io/streams check-write allowance for WASIp2 outgoing HTTP bodies. This flaw permits a malicious guest to write oversized buffers to outgoing HTTP body resources, causing host memory exhaustion by holding allocations for the store's lifetime.
CVE-2026-115387 is a denial of service vulnerability in bytecodealliance's wasmtime-wasi component. It affects multiple version ranges of wasmtime before specific fixed versions. The flaw allows guest WASI programs to cause the host to panic by passing filesystem timestamp values with overflowing sub-second fields, leading to a crash.
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 leftover host stack or heap memory per directory entry.
Wasmtime versions 46.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contain a denial of service vulnerability in the wasmtime-wasi WASIp3 implementation. This flaw allows guests with mutable preopened directory access to cause the Unix host process to abort by invoking set-times or set-times-at with negative timestamps before the epoch, triggering an assertion failure that crashes the host.
CVE-2026-115384 is a critical stack buffer overflow vulnerability in bytecodealliance's wasmtime affecting versions 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2. It arises from improper input validation of async callback result types, allowing malicious guests to write approximately 16KB to the native stack. This can lead to crashing the host or escaping the sandbox environment.
Wasmtime versions 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 have an improper validation vulnerability related to WebAssembly tags with subtypes. This flaw allows malicious guests to mis-type exception object payloads, potentially corrupting the garbage-collected heap and causing Wasmtime to panic when the exceptions proposal is enabled.
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 the host embedding.
CVE-2026-115381 is a medium severity vulnerability in bytecodealliance's wasmtime. It involves unbounded memory allocation in the wasmtime-wasi WASIp2 write-zeroes method of SinkOutputStream, which is the default stream when stdout/stderr are not configured. Malicious WebAssembly guests can exploit this to request large zero-filled writes, exhausting host memory and causing denial of service. The issue affects wasmtime versions before 36.0.17, versions from 37.0.0 up to but not including 48.0.4, and versions from 49.0.0 up to but not including 49.0.2.
CVE-2026-115380 is a denial of service vulnerability in the wasmtime-wasi WASI preview 0 poll_oneoff adapter of the wasmtime runtime. It affects versions before 36.0.17, versions from 37.0.0 up to but not including 48.0.4, and versions from 49.0.0 up to but not including 49.0.2. The vulnerability arises because the adapter performs O(n) host work per subscription without consuming or checking fuel, allowing malicious guest modules to cause long-running host computations that ignore configured fuel limits.
CVE-2026-115379 is a use-after-free vulnerability in bytecodealliance's wasmtime affecting versions 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2. The flaw involves missing garbage collection rooting that leaves references unrooted across try_call when compiling WebAssembly modules. This can cause garbage collection heap corruption or incorrect execution when attackers supply specially crafted Wasm modules.
Wasmtime is a runtime for WebAssembly. Prior to 24.0.11, 36.0.12, 45.0.3, and 46.0.1, wasmtime-wasi hard-link creation and renaming check directory permissions but not matching FilePerms on source and destination preopens, allowing a WASI guest with a read-only source file capability to overwrite host files exposed as FilePerms::READ through wasip1, wasip2, or wasip3 filesystem interfaces. This issue is fixed in versions 24.0.11, 36.0.12, 45.0.3, and 46.0.1.
Wasmtime is a runtime for WebAssembly. All versions prior to 24.0.10; versions 25.0.0 through those before 36.0.11; versions 37.0.0 through those before 44.0.3; and versions 45.0.0 and 45.0.1 contain a native implementation of WASIp1 which suffers from a leak in the fd_renumber function where the file descriptor being renumbered to is not properly closed. Wasmtime's implementation erroneously only updated the table of descriptors for WASIp1 and didn't update the underlying table of descriptors used by the host. This behavior means that while fd_renumber works correctly from a guest's perspective it ends up leaking resources in the host that aren't cleaned up until the corresponding Store is destroyed. In a loop, guests can use fd_renumber to cause hosts to exhaust both resources and file descriptors. This bug only affects the native implementation of WASIp1, meaning that only runtimes which load core wasm modules and expose fd_renumber are affected. Runtimes are additionally only affected if they expose the ability to acquire a file descriptor, such as opening a file. For runtimes that deny access to files they are unaffected. This issue has been fixed in versions 24.0.10, 36.0.11, 44.0.3, and 45.0.2.