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CRITICAL

CVE-2026-93603

CVE-2026-93603 — vm2 before 3.12.1 Sandbox Escape RCE via Non-Strict Host Function

vm2 through 3.12.0 (fixed in 3.12.1) does not correctly handle a nullish `this` receiver in the apply trap of its bridge (lib/bridge.js): when sandboxed code calls a host-provided non-strict (sloppy-mode) function without a receiver — e.g. `fn()`, a detached method, `fn.call()`, `fn.apply(undefined)`, `Reflect.apply(fn, undefined, [])`, or `fn.bind()()` — the undefined receiver is passed straight through to the host call, and V8 substitutes the host realm's global object for `this`. vm2 then wraps and returns that object to the sandbox, giving sandboxed script a live proxy of the host global. This allows a complete sandbox escape: untrusted script can reach `process` and execute arbitrary code/commands on the host (for example via `process.getBuiltinModule('child_process').execSync`). Exploitation requires that the embedding application expose at least one non-strict host function to…

Published Updated Sources: cvelistV5, VulnCheck

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

1%

chance of exploitation in 30 days

Affects

patriksimek

vm2

CVSS base

10

CRITICAL

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

PoC

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

patriksimek

Products (1)

vm2

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
10CVSS 3.1CRITICAL——cvelistV5

Weakness & attack patterns

  • CWE-94

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

  • T1027.006Obfuscated Files or Information: HTML Smuggling
  • T1027.009Obfuscated Files or Information: Embedded Payloads
  • T1564.009Hide Artifacts: Resource Forking

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

  • Search application, proxy, and WAF logs for requests touching /bridge.js), /commands.

References

2 on the record

Elsewhere on this site

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.