Bytecode Alliance wasm-micro-runtime up to 2.4.4 WASI POSIX libc_wasi_wrapper.c wasi_poll_oneoff/wasmtime_ssp_poll_oneoff heap-based overflow

Summaryinfo

A vulnerability classified as critical has been found in Bytecode Alliance wasm-micro-runtime up to 2.4.4. Affected by this vulnerability is the function wasi_poll_oneoff/wasmtime_ssp_poll_oneoff of the file core/iwasm/libraries/libc-wasi/libc_wasi_wrapper.c of the component WASI POSIX. This manipulation causes heap-based overflow. This vulnerability appears as CVE-2026-54914. The attack may be initiated remotely. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Bytecode Alliance wasm-micro-runtime up to 2.4.4 and classified as critical. Affected by this vulnerability is the function wasi_poll_oneoff/wasmtime_ssp_poll_oneoff of the file core/iwasm/libraries/libc-wasi/libc_wasi_wrapper.c of the component WASI POSIX. The manipulation with an unknown input leads to a heap-based overflow vulnerability. The CWE definition for the vulnerability is CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Prior to 2.4.5, wasi_poll_oneoff in core/iwasm/libraries/libc-wasi/libc_wasi_wrapper.c validates the output pointer for only one wasi_event_t, while wasmtime_ssp_poll_oneoff in core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/src/posix.c can write as many events as the guest-controlled nsubscriptions value. A crafted guest module can provide multiple subscriptions that produce events while positioning an output region large enough for only one event, causing a later out[nevents] write to cross the validated Wasm linear-memory boundary into adjacent host heap memory. The overwrite contains partly attacker-controlled event data and can reliably crash the host process, with further confidentiality or integrity consequences depending on heap layout. This issue is fixed in version 2.4.5.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-54914 since 06/16/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 2.4.5 eliminates this vulnerability.

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Productinfo

Vendor

• Bytecode Alliance

Name

• wasm-micro-runtime

Version

• 2.4.0
• 2.4.1
• 2.4.2
• 2.4.3
• 2.4.4

CPE 2.3info

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CPE 2.2info

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