{"id":"CVE-2026-115391","title":"Wasmtime 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4 Unbounded Heap Allocation via WASIp3 Streams","summary":"Wasmtime 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4 contains an uncontrolled resource allocation vulnerability in its WASIp3 implementation that buffers guest-specified-length writes on the host without limit. Malicious guests can off…","severity":"medium","cvss":5.8,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-770"],"vendor":"bytecodealliance","product":"wasmtime","affected":["wasmtime >= 46.0.0 < 46.0.3","wasmtime >= 47.0.0 < 47.0.4"],"published":"2026-10-22","updated":"2026-10-22","sourceUpdated":"2026-10-22T19:13:57.752Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-115391","references":[{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-x84v-gj2h-g759","label":"GitHub Security Advisory (GHSA-x84v-gj2h-g759)"},{"url":"https://www.vulncheck.com/advisories/wasmtime-46.0.0-before-46.0.3-and-47.0.0-before-47.0.4-unbounded-heap-allocation-via-wasip3-streams","label":"VulnCheck Advisory: Wasmtime 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4 Unbounded Heap Allocation via WASIp3 Streams"}],"tags":["cve.org"],"ingestedAt":"2026-10-22T22:00:50.406Z","slug":"CVE-2026-115391","body":"## Overview\n\nWasmtime 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4 contains an uncontrolled resource allocation vulnerability in its WASIp3 implementation that buffers guest-specified-length writes on the host without limit. Malicious guests can offer large buffers to WASIp3 file or HTTP write streams, causing the host to copy and buffer all bytes, bounded only by guest linear memory, exhausting host memory.\n\n## Affected\n\n- `wasmtime >= 46.0.0 < 46.0.3`\n- `wasmtime >= 47.0.0 < 47.0.4`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":32,"depthScoreParts":{"impact":31.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}