How severe is CVE-2026-43999?

CVE-2026-43999 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-43999 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-43999?

CVE-2026-43999 affects Vm2 Project Vm2. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-43999?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-43999 have an EU (EUVD) identifier?

Yes. CVE-2026-43999 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30069.

When was CVE-2026-43999 published?

CVE-2026-43999 was published on 2026-05-13 and last updated on 2026-06-30.

CVE-2026-43999

CVE-2026-43999 is a critical-severity vulnerability in Vm2 Project Vm2 with a CVSS 3.x base score of 9.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-863.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
EPSS exploit prediction: 1% (58th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-30069
Weakness: CWE-863
Affected product: Vm2 Project Vm2
Published: 2026-05-13
Last modified: 2026-06-30

Description

vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.0, NodeVM's builtin allowlist can be bypassed when the module builtin is allowed (including via the '*' wildcard). The module builtin exposes Node's Module._load(), which loads any module by name directly in the host context, completely bypassing vm2's builtin restriction. This allows sandboxed code to load excluded builtins like child_process and achieve remote code execution. This vulnerability is fixed in 3.11.0.

Frequently asked questions

What is CVE-2026-43999?: vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.0, NodeVM's builtin allowlist can be bypassed when the module builtin is allowed (including via the '*' wildcard). The module builtin exposes Node's Module._load(), which loads any module by name directly in the host context, completely bypassing vm2's builtin restriction. This allows sandboxed code to load excluded builtins like child_process and achieve remote code execution. This vulnerability is fixed in 3.11.0.
How severe is CVE-2026-43999?: CVE-2026-43999 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-43999 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-43999?: CVE-2026-43999 affects Vm2 Project Vm2. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-43999?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-43999 have an EU (EUVD) identifier?: Yes. CVE-2026-43999 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30069.
When was CVE-2026-43999 published?: CVE-2026-43999 was published on 2026-05-13 and last updated on 2026-06-30.

References

Affected products (1)

cpe:2.3:a:vm2_project:vm2:*:*:*:*:*:node.js:*:*

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