{"id":"CVE-2026-100723","title":"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","summary":"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 th…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N","cwe":["CWE-200","CWE-653","CWE-787"],"vendor":"patriksimek","product":"vm2","affected":["vm2 < 3.12.2"],"published":"2026-09-27","updated":"2026-10-01","sourceUpdated":"2026-10-01T19:17:16.563","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-100723","references":[{"url":"https://github.com/patriksimek/vm2/commit/4f2508abeb252aa86eb6761c78b3b000248fb089","label":"disclosure@vulncheck.com"},{"url":"https://github.com/patriksimek/vm2/commit/5214b02ef13b82497fcb917b45320dfd014ffd09","label":"disclosure@vulncheck.com"},{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-489w-w794-jq94","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/vm2-before-3.12.2-memory-disclosure-via-zlib-buffer-pool","label":"disclosure@vulncheck.com"},{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-489w-w794-jq94","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100723.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-100723"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2542016"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-100723"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100723"},{"url":"https://github.com/patriksimek/vm2/commit/9596bf5e7d8de7351d675ff4f5293b72157202d4"},{"url":"https://github.com/patriksimek/vm2/releases/tag/v3.12.2"},{"url":"https://github.com/advisories/GHSA-489w-w794-jq94"}],"tags":["nvd","cve.org","csaf","vex","red-hat","exploit-available","ghsa","npm","score-dispute"],"epss":0.00392,"epssPercentile":0.33118,"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-01T18:04:51.057802Z"},"ingestedAt":"2026-09-27T02:41:45.566Z","aliases":["GHSA-489w-w794-jq94"],"ecosystem":"npm","patched":["vm2 3.12.2"],"scores":{"nvd":7.5,"ghsa":10},"slug":"CVE-2026-100723","body":"## Overview\n\nvm2 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · updated 2026-09-28 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100723.json)\n\n## Package advisory (CVE-2026-100723)\n\nAffected packages:\n\n- `vm2 <= 3.12.1`\n\nPatched in:\n\n- `vm2 3.12.2`\n\nSource: https://github.com/advisories/GHSA-489w-w794-jq94","depth":"midnight","depthScore":53,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":214615,"id":"CVE-2026-100723","ts":1790881126646,"field":"exploit_available","old":"false","new":"true"}]}