{"id":"CVE-2026-100723","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-100723","generatedAt":"2026-10-27T22:46:36.115Z","title":"When an application explicitly exposes Node's zlib module through NodeVM's builtin allowlist (require: { builtin: ['zlib'] }), zlib.deflateSync can return a Buffer backed by Node's shared small-buffer pool whose .buffer is the entire pool.","description":"vm2 before 3.12.2 does not apply its Buffer backing-store ownership invariant (byteOffset === 0 and buffer.byteLength === length) to Buffers returned from host builtin modules. When an application explicitly exposes Node's zlib module through NodeVM's builtin allowlist (require: { builtin: ['zlib'] }), zlib.deflateSync can return a Buffer backed by Node's shared small-buffer pool whose .buffer is the entire pool. Untrusted guest code can construct a full-width view of that ArrayBuffer (Buffer.from(result.buffer, 0, result.buffer.byteLength)) to read and modify bytes belonging to unrelated host buffers, disclosing and corrupting host-realm memory across the sandbox boundary.","published":"2026-09-27T02:17:19.000Z","lastModified":"2026-10-01T19:17:17.000Z","status":"Deferred","sourceIdentifier":"disclosure@vulncheck.com","cvss":{"version":"4.0","score":6.9,"severity":"MEDIUM","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-200"],"affected":[],"epss":{"score":0.00392,"percentile":0.33045,"date":"2026-10-26","history":[{"date":"2026-09-27","score":0.00316,"percentile":0.21992}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.39%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-09-27T02:17:19.000Z","detail":{"score":"6.9","severity":"MEDIUM","publishedAt":"2026-09-27T02:17:19.373Z"},"summary":"New CVE, medium severity (CVSS 6.9)."}],"references":[{"url":"https://github.com/patriksimek/vm2/commit/4f2508abeb252aa86eb6761c78b3b000248fb089","source":"disclosure@vulncheck.com"},{"url":"https://github.com/patriksimek/vm2/commit/5214b02ef13b82497fcb917b45320dfd014ffd09","source":"disclosure@vulncheck.com"},{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-489w-w794-jq94","source":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/vm2-before-3.12.2-memory-disclosure-via-zlib-buffer-pool","source":"disclosure@vulncheck.com"},{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-489w-w794-jq94","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-100723","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}