CVE-2026-100723
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- https://github.com/patriksimek/vm2/commit/4f2508abeb252aa86eb6761c78b3b000248fb089
- https://github.com/patriksimek/vm2/commit/5214b02ef13b82497fcb917b45320dfd014ffd09
- https://github.com/patriksimek/vm2/security/advisories/GHSA-489w-w794-jq94
- https://www.vulncheck.com/advisories/vm2-before-3.12.2-memory-disclosure-via-zlib-buffer-pool
CWEs
CWE-200
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.