CVE-2026-100723
vm2 before 3.12.2 Memory Disclosure via zlib Buffer Pool
MEDIUM 6.9
At a glance
- Source
- NVD
- EPSS
- EPSS 0.39 % · percentile 33 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- VulnCheck
- NVD status
- Deferred
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.
Weaknesses (CWE)
- CWE-200 — Exposure of Sensitive Information to an Unauthorized Actor
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
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | MEDIUM 6.9 | 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 | VulnCheck |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N | VulnCheck |
| CVSS 4.0 | MEDIUM 6.9 | 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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · disclosure@vulncheck.com (Secondary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N | NVD · disclosure@vulncheck.com (Secondary) |
Advisories
- GHSA-489w-w794-jq94 — vm2: NodeVM zlib Buffers expose pooled host memory across the VM boundary
European references
- ENISA EUVD · EUVD-2026-87856
- GCVE · GCVE-0-2026-100723
Affected products
| Product | Versions |
|---|---|
| patriksimek · vm2 | affected 0 < 3.12.2 ; unaffected 3.12.2 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |