Information disclosure in Patriksimek Vm2
CVE-2026-100723
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.
Vulnerability class: Information Disclosure
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (33.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 34th percentile — 33.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
Weakness classification (CWE)
References
- GitHub Security Advisory (GHSA-489w-w794-jq94) (vendor-advisory)
- Patch Commit (patch)
- Patch Commit (patch)
- VulnCheck Advisory: vm2 before 3.12.2 Memory Disclosure via zlib Buffer Pool (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100723?
- CVE-2026-100723 is a high-severity vulnerability in Patriksimek Vm2, classified under Information Disclosure. CVSS score: 7.5/10. Published 2026-09-27.
- How severe is CVE-2026-100723?
- High severity. CVSS v3 base score is 7.5 out of 10.