CVE-2026-92952: patriksimek vm2

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 0.5%, percentile 39: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 39% 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 versions 3.11.4 through 3.11.6 incompletely filter Node.js registered internal symbols across the sandbox boundary. The extraction filters in lib/setup-sandbox.js and the cross-realm symbol checks and write traps in lib/bridge.js use a fixed list of known dangerous registered symbols that omits nodejs.stream.disturbed and nodejs.stream.errored, which are exposed on host WebStream prototypes on newer Node.js releases (validated on Node.js v25.8.0). When the embedder exposes a host WebStream object and the host stream/web module to the sandbox, sandbox code can obtain the real host symbols via Object.getOwnPropertySymbols(streamWeb.ReadableStream.prototype) and use them as write keys on host stream objects, corrupting host-visible stream state — for example making stream.Readable.isDisturbed() return false for an already-consumed stream. This can bypass host logic that relies on Node's public stream-state helpers to enforce one-shot body consumption, reject errored streams, or decide whether a stream is safe to hand to another component. It is not a host code-execution primitive in the reported proof of vulnerability. This is an incomplete fix for the earlier nodejs. symbol filtering issue. Fixed in vm2 3.11.7.

Weakness type: CWE-669.

Product: patriksimek vm2 · Assigned by: VulnCheck · Published: 2026-09-17

Affected and fixed versions

Vendor	Product	Affected versions (per CVE record)
patriksimek	vm2	3.11.4 < 3.11.7

Severity scores

Scored by	CVSS	Score	Vector
VulnCheck	4.0	8.9 High	`CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N`
VulnCheck	3.1	6.8 Medium	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N`

Attack vector: network (remotely reachable)
Attack complexity: high (needs special conditions)
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): 0.46% probability of exploitation activity in the next 30 days; percentile 39.

Timeline

2026-08-17 — erroneo.us brief: vm2: 22 Critical Sandbox Escapes, Fixed in 3.12.2
2026-09-17 — CVE record last updated
2026-09-17 — CVE record published by VulnCheck

Sources and references

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