CVE-2026-47683 vm2: bufferAllocLimit cap bypassed by Buffer.concat and Buffer.from arrayLike
Sandboxed code can bypass memory limits via Buffer operations, causing host process exhaustion and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-47683?
CVE-2026-47683 is a high-severity denial of service vulnerability in patriksimek vm2, published on 17 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.6, the bufferAllocLimit enforcement in lib/setup-sandbox.js does not cover Buffer.concat(list, totalLength) or Buffer.from(arrayLike) with an attacker-controlled length, allowing sandbox code to perform large synchronous host external-memory allocations that bypass the configured cap and can exhaust the host process. This issue is fixed in version 3.11.6.
Weakness: CWE-770
Which versions are affected by CVE-2026-47683?
2 open source packages ship an affected version, including vm2.
| Package | Affected | Fixed in |
|---|---|---|
vm2 npm | All versions | 3.11.6 |
vm2 npm | All versions | 3.11.6 |
How do I fix CVE-2026-47683?
Upgrade vm2 to 3.11.6 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-47683 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-47683 exists.
Sources
Also known as CLEANSTART-2026-MK88618, ECHO-a5bc-78ae-239f, GHSA-gmc2-2x9w-cgh9, MINI-pcj6-6944-24f3, ROOT-APP-NPM-CVE-2026-47683.