CVE-2026-92953: vm2 (npm)

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. 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 0.5%, percentile 42: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 42% 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.
Only applies if your dependency tree includes vm2 (npm) >= 3.11.0, <= 3.11.7, fixed in 3.11.8. Check your lockfile, including transitive dependencies.
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 versions from 3.11.0 before 3.11.8 fail to protect host TypedArray and ArrayBuffer prototypes from sandbox mutation. Attackers can use prototype-walking primitives to reach and modify host Uint8Array.prototype, %TypedArray%.prototype, and ArrayBuffer.prototype, causing host-created typed arrays to observe attacker-controlled properties after VM.run() returns.

From the GitHub advisory

Summary

vm2's current host-intrinsic prototype protection is incomplete. The fix for GHSA-vwrp-x96c-mhwq blocks sandbox writes into classic host intrinsics such as Object.prototype, Array.prototype, and Function.prototype, but current head still lets sandbox code in a default VM reach and mutate host Uint8Array.prototype, %TypedArray%.prototype, and ArrayBuffer.prototype.

After VM.run() returns, normal host typed-array and ArrayBuffer objects observe attacker-controlled properties and methods installed by the sandbox.

Technical Details

The existing mitigation relies on protectedHostObjects in lib/bridge.js. That set is populated from otherGlobalPrototypes, which is built from a fixed inventory of classic globals:

Weakness type: CWE-913, CWE-1321.

Product: vm2 (npm) · Assigned by: VulnCheck · Published: 2026-09-17

Affected and fixed versions

Ecosystem	Package	Vulnerable	First fixed
npm	`vm2`	>= 3.11.0, <= 3.11.7	3.11.8

Vendor	Product	Affected versions (per CVE record)
patriksimek	vm2	3.11.0 < 3.11.8

Severity scores

Scored by	CVSS	Score	Vector
VulnCheck	4.0	9.3 Critical	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H`
VulnCheck	3.1	10 Critical	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H`
GitHub	4.0	9.3	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H`

Attack vector: network (remotely reachable)
Attack complexity: low
Attack requirements: none
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 yes, technical impact partial.
FIRST EPSS (model of 2026-10-21): 0.50% probability of exploitation activity in the next 30 days; percentile 42.

Timeline

2026-08-17 — erroneo.us brief: vm2: 22 Critical Sandbox Escapes, Fixed in 3.12.2
2026-09-17 — CVE record published by VulnCheck
2026-09-18 — CVE record last updated
2026-10-05 — GitHub-reviewed advisory GHSA-3vgf-8m4q-q4qr published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.