{"id":"CVE-2026-100723","state":"PUBLISHED","title":"vm2 before 3.12.2 Memory Disclosure via zlib Buffer 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.","publishedAt":"2026-09-27T01:28:30.027Z","updatedAt":"2026-10-01T18:04:57.414Z","severity":{"score":6.9,"label":"Medium","version":"4.0","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","source":"VulnCheck"},"assigner":"VulnCheck","products":["patriksimek vm2"],"affected":[{"vendor":"patriksimek","product":"vm2","packageURL":"pkg:npm/vm2","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"3.12.2","versionType":"semver"},{"version":"3.12.2","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/patriksimek/vm2/security/advisories/GHSA-489w-w794-jq94","https://github.com/patriksimek/vm2/commit/4f2508abeb252aa86eb6761c78b3b000248fb089","https://github.com/patriksimek/vm2/commit/5214b02ef13b82497fcb917b45320dfd014ffd09","https://www.vulncheck.com/advisories/vm2-before-3.12.2-memory-disclosure-via-zlib-buffer-pool"],"weaknesses":["CWE-200"],"ingestedAt":"2026-10-29T20:10:13.529Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/100xxx/CVE-2026-100723.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-100723","state":"PUBLISHED","datePublished":"2026-09-27T01:28:30.027Z","dateUpdated":"2026-10-01T18:04:57.414Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-09-26T02:40:56.226Z"},"containers":{"cna":{"title":"vm2 before 3.12.2 Memory Disclosure via zlib Buffer Pool","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"patriksimek","product":"vm2","packageURL":"pkg:npm/vm2","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"3.12.2","versionType":"semver"},{"version":"3.12.2","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-489w-w794-jq94","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-489w-w794-jq94)"},{"url":"https://github.com/patriksimek/vm2/commit/4f2508abeb252aa86eb6761c78b3b000248fb089","tags":["patch"],"name":"Patch Commit"},{"url":"https://github.com/patriksimek/vm2/commit/5214b02ef13b82497fcb917b45320dfd014ffd09","tags":["patch"],"name":"Patch Commit"},{"url":"https://www.vulncheck.com/advisories/vm2-before-3.12.2-memory-disclosure-via-zlib-buffer-pool","name":"VulnCheck Advisory: vm2 before 3.12.2 Memory Disclosure via zlib Buffer Pool","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"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","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"LOW","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"LOW","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-200","lang":"en","description":"Exposure of Sensitive Information to an Unauthorized Actor","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-09-27T01:28:30.027Z"},"datePublic":"2026-09-08T00:00:00.000Z","credits":[{"lang":"en","value":"rexpository","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-489w-w794-jq94","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-01T18:04:51.057802Z","id":"CVE-2026-100723","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-01T18:04:57.414Z"}}]}}}