Skip to content
Fencer Vulns
critical 10.0

CVE-2026-93603 json

vm2 before 3.12.1 Sandbox Escape RCE via Non-Strict Host Function

published 2026-09-18 52 d ago modified 2026-09-22 48 d ago also EUVD-2026-82898

cvss
10.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 54%
public exploits
0
none known

Summary

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 the sandbox; strict-mode and ES module host functions are not affected.

Patch / fix

  • patriksimek vm2 3.12.1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-93603 updated cvss 9.8

vm2: vm2 before 3.12.1 Sandbox Escape RCE via Non-Strict Host Function

  • Red Hat Ansible Automation Platform 2.1 ansible-automation-platform/automation-portal 1791295379
    fixed: vendor fix “Until the fix is applied, do not expose non-strict host functions to the sandbox. Only inject strict-mode or ES-module functions so a missing this cannot resolve to the host global.” RHSA-2026:80603
  • Red Hat Ansible Automation Platform 2.2 ansible-automation-platform/automation-portal 1791293780, ansible-automation-platform/bootc-automation-portal-rhel9 1791865660
    fixed: vendor fix “Until the fix is applied, do not expose non-strict host functions to the sandbox. Only inject strict-mode or ES-module functions so a missing this cannot resolve to the host global.” RHSA-2026:80644
  • Red Hat Developer Hub 1.9 rhdh/rhdh-hub-rhel9 1793117813
    fixed: vendor fix “Until the fix is applied, do not expose non-strict host functions to the sandbox. Only inject strict-mode or ES-module functions so a missing this cannot resolve to the host global.” RHSA-2026:91651
  • Red Hat Developer Hub 1.10 rhdh/rhdh-hub-rhel9 1791311495, rhdh/red-hat-developer-hub-backstage-plugin-lightspeed-backend 1791242697, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend 1791251282
    fixed: vendor fix “Until the fix is applied, do not expose non-strict host functions to the sandbox. Only inject strict-mode or ES-module functions so a missing this cannot resolve to the host global.” RHSA-2026:76788
  • Red Hat Developer Hub 1.9 rhdh/rhdh-rhel9-operator 1793117972, rhdh/rhdh-operator-bundle 1793126835 Red Hat Developer Hub 1.10 rhdh/rhdh-rhel9-operator 1791219676, rhdh/rhdh-operator-bundle 1791315788, rhdh/rhdh-must-gather-rhel9 1788278523, rhdh/rhdh-rag-content-rhel9 1791168570, rhdh/red-hat-developer-hub-backstage-plugin-lightspeed 1791242743, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator 1791250003, +3 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
48 d ago

Exploit prediction

0.73% chance of exploitation in the next 30 days, higher than 54% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/patriksimek/vm2/security/advisories/GHSA-j89j-5m6r-cr2q referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 10.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CNA 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CNA 4.0 10.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • patriksimek vm2

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.