CVE-2026-100723vm2 before 3.12.2 Memory Disclosure via zlib Buffer Pool
Updated under an hour ago ()
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It affects patriksimek vm2. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.32%, higher than 23% of scored CVEs.
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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.
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N
- Weakness (CWE)
- CWE-200
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.32% (percentile 23)
- Assigned by
- VulnCheck
- NVD analysis
- Deferred
- Record last updated
- Oct 1, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
patriksimek vm2 patriksimek:vm2 (from the name) | before 3.12.2; 3.12.2 not affected | CNA record |
References
- https://github.com/patriksimek/vm2/security/advisories/GHSA-489w-w794-jq94vendor-advisory
- https://github.com/patriksimek/vm2/commit/4f2508abeb252aa86eb6761c78b3b000248fb089patch
- https://github.com/patriksimek/vm2/commit/5214b02ef13b82497fcb917b45320dfd014ffd09patch
- https://www.vulncheck.com/advisories/vm2-before-3.12.2-memory-disclosure-via-zlib-buffer-poolthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.