Security Digest · Vulnerability record
CVE-2026-100722: vm2 before 3.12.2 Host Process Termination via Construct Trap
vm2 before 3.12.2 does not apply host-side Promise rejection handling in the sandbox-to-host construct trap.
CVSS 8.9 High EPSS 0.3% · p17 Check exposure
Should you act?
Normal patch cycle
No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.3%, percentile 17: FIRST’s model estimates a 0.3% chance of exploitation activity in the next 30 days, higher than 17% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Check exposure. vm2: 22 Critical Sandbox Escapes, Fixed in 3.12.2 — If anything outside your trust boundary can get code into vm2, upgrade to 3.12.2 today and plan to move that code out of process; if vm2 only runs your own code, upgrade on a normal cycle.
What it is
vm2 before 3.12.2 does not apply host-side Promise rejection handling in the sandbox-to-host construct trap. In BaseHandler, the apply trap calls markHostPromiseHandled() on the returned value, but the adjacent construct path returns the result of Reflect.construct without the same sanitization. If an embedder exposes a constructable host function whose constructor returns a native rejected Promise, an untrusted script executed via VM.run can invoke it with new and ignore the result; the rejected host Promise crosses the bridge unhandled and, under Node's strict unhandled-rejection policy, is promoted to an uncaught exception that terminates the host process.
Weakness type: CWE-248.
Product: patriksimek vm2 · Assigned by: VulnCheck · Published: 2026-09-27
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| patriksimek | vm2 | < 3.12.2 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulnCheck | 4.0 | 8.9 High | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H |
| VulnCheck | 3.1 | 6.8 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: present (depends on deployment conditions)
- Privileges required: none (no login)
- User interaction: none
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable no, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 0.26% probability of exploitation activity in the next 30 days; percentile 17.
Timeline
- — erroneo.us brief: vm2: 22 Critical Sandbox Escapes, Fixed in 3.12.2
- — CVE record published by VulnCheck
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
Vulnerability records
- CVE.org record CVE-2026-100722 cve.org
- NVD entry CVE-2026-100722 nvd.nist.gov