vulnerability / NVI-00015108 / Revision 2
vm2's bufferAllocLimit cap bypassed by Buffer.concat and Buffer.from arrayLike
GitHub lists this reviewed advisory for vm2. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
8.7 HIGH (4.0)
security-advisories@github.com severity; no combined Null risk score.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
vm2
source listed<= 3.11.5
## Summary vm2 bufferAllocLimit cap bypassed by Buffer.concat and Buffer.from arrayLike The `bufferAllocLimit` option introduced in 3.11.0 (GHSA-6785-pvv7-mvg7) caps host-side Buffer allocations driven by sandbox code, the way embedders opt into `timeout`. The cap wraps `Buffer.alloc`, `Buffer.allocUnsafe`, `Buffer.allocUnsafeSlow`, and the deprecated `Buffer(N)` / `new Buffer(N)` forms. Two other API paths reach the same host C++ allocator with an attacker-controlled size and are not capped: `Buffer.concat(list, totalLength)` and `Buffer.from(arrayLike)` with a fake `length`. Sandbox code can use either to allocate an arbitrary number of host external bytes in a single call, defeating the explicit DoS mitigation the embedder configured. ## Details `lib/setup-sandbox.js` installs `checkBufferAllocLimit` at every wrapped entry to host Buffer allocation: - `alloc()` at `lib/setup-sandbox.js:474` and the `connect(alloc, host.Buffer.alloc)` at line 480. - `allocUnsafe()` at line 488 and `connect(allocUnsafe, host.Buffer.allocUnsafe)` at line 496. - `allocUnsafeSlow()` at line 504 and `connect(allocUnsafeSlow, host.Buffer.allocUnsafeSlow)` at line 510. - `BufferHandler.apply` at li
03 / Response
What to do next
- investigate
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A fixed release is not deployment evidence.
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
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05 / Provenance
Sources you can inspect
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- GHSA-gmc2-2x9w-cgh9 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-47683 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 2 ·
Source facts changed; compare the preserved prior revision.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.