{"id":"CVE-2026-54914","title":"WebAssembly Micro Runtime: Heap Buffer Overflow in WAMR WASI poll_oneoff Output Buffer","summary":"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…","severity":"high","cvss":8.3,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N","cvssSource":"cna","cwe":["CWE-122"],"vendor":"bytecodealliance","product":"wasm-micro-runtime","affected":["wasm-micro-runtime < 2.4.5"],"published":"2026-11-05","updated":"2026-11-05","sourceUpdated":"2026-11-05T17:27:16.493Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-54914","references":[{"url":"https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-wj3p-xhqm-pffc","label":"https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-wj3p-xhqm-pffc"},{"url":"https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/1f98fb01d09b2ef5e49dc0be2e6006f962fd87f1","label":"https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/1f98fb01d09b2ef5e49dc0be2e6006f962fd87f1"},{"url":"https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/b49d10eac4176817305d60ea59d24bc69a53eb7b","label":"https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/b49d10eac4176817305d60ea59d24bc69a53eb7b"},{"url":"https://github.com/wasm-micro-runtime/wasm-micro-runtime/releases/tag/WAMR-2.4.5","label":"https://github.com/wasm-micro-runtime/wasm-micro-runtime/releases/tag/WAMR-2.4.5"}],"tags":["cve.org"],"ingestedAt":"2026-11-05T22:38:31.438Z","slug":"CVE-2026-54914","body":"## Overview\n\nWebAssembly 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.\n\n## Affected\n\n- `wasm-micro-runtime < 2.4.5`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":46,"depthScoreParts":{"impact":45.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}