{"id":"CVE-2026-115381","title":"Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 Unbounded Host Memory Allocation via SinkOutputStream write-zeroes","summary":"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 confi…","severity":"medium","cvss":4.8,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-770"],"vendor":"bytecodealliance","product":"wasmtime","affected":["wasmtime < 36.0.17","wasmtime >= 37.0.0 < 48.0.4","wasmtime >= 49.0.0 < 49.0.2"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-26T19:27:26.922435Z"},"published":"2026-10-22","updated":"2026-10-26","sourceUpdated":"2026-10-26T19:38:29.893Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-115381","references":[{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-gqmc-89g8-p25r","label":"GitHub Security Advisory (GHSA-gqmc-89g8-p25r)"},{"url":"https://www.vulncheck.com/advisories/wasmtime-before-36.0.17-37.0.0-before-48.0.4-and-49.0.0-before-49.0.2-unbounded-host-memory-allocation-via-sinkoutputstream-write-zeroes","label":"VulnCheck Advisory: Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 Unbounded Host Memory Allocation via SinkOutputStream write-zeroes"},{"url":"https://crates.io/crates/wasmtime-wasi"},{"url":"https://rustsec.org/advisories/RUSTSEC-2026-0322.html"},{"url":"https://github.com/bytecodealliance/wasmtime/pull/14482"}],"tags":["cve.org","osv","rust"],"epss":0.00212,"epssPercentile":0.11382,"aliases":["RUSTSEC-2026-0322","GHSA-gqmc-89g8-p25r"],"ecosystem":"rust","patched":["wasmtime-wasi 49.0.2"],"ingestedAt":"2026-10-22T22:00:50.403Z","slug":"CVE-2026-115381","body":"## Overview\n\nWasmtime 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 zero-filled writes, exhausting host memory and causing denial of service.\n\n## Affected\n\n- `wasmtime < 36.0.17`\n- `wasmtime >= 37.0.0 < 48.0.4`\n- `wasmtime >= 49.0.0 < 49.0.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-115381)\n\nAffected packages:\n\n- `wasmtime-wasi >= 49.0.0, < 49.0.2`\n\nPatched in:\n\n- `wasmtime-wasi 49.0.2`\n\nSource: https://osv.dev/vulnerability/RUSTSEC-2026-0322","depth":"sunlit","depthScore":26,"depthScoreParts":{"impact":26.4,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}