What is CVE-2026-92959?

CVE-2026-92959 is vm2 before 3.11.8 allowAsync Bypass via Promise Thenable. The supplied enrichment data classifies it as Unclassified mapped to CWE-693 CWE-693.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Active exploitation is not confirmed from current sources for CVE-2026-92959. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-92959 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

1 public PoC repositories reported; 0 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-92959 using CVSS 7.1, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Prioritize based on EPSS, PoC availability, and external exposure. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

highpublic exploit

CVE-2026-92959

CVE-2026-92959 — vm2 before 3.11.8 allowAsync Bypass via Promise Thenable

vm2 before 3.11.8 does not fully enforce the allowAsync: false option in VM and NodeVM. While localPromise.prototype.then is replaced with a handler that throws 'Async not available', the sandbox's Promise static methods (Promise.resolve, Promise.all, Promise.race, Promise.any, and Promise.allSettled) still assimilate attacker-supplied thenables: native promise resolution performs PromiseResolveThenableJob and invokes the sandboxed code's then method in a microtask without passing through the patched then, so the async restriction is never applied. As a result, sandboxed script can schedule work that runs after VM.run() or NodeVM.run() has returned and outside the configured timeout, continuing to execute after the host believes execution is complete.

Published Sep 17, 2026Updated Sep 17, 2026Sources: NVD, patriksimek (CNA), GitHub, GitHub Security Advisory, Red Hat (VEX), SOCRadar CTI

Triage

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

Exploitation

Exploit code

public exploit, none observed

EPSS

ahead of 0% of scored CVEs

Affects

patriksimek

2 products listed

CVSS base

7.1

high · 2 sources

Remediation

The vendor's own words where we have them.

Upgrade vm2 to a fixed release (3.11.8). Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

Red Hat VEX · CVE-2026-92959

fixed0affected0not affected1

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Prioritize based on EPSS, PoC availability, and external exposure.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
patriksimek	vm2	0 to < 3.11.8	Vulnerable
patriksimek	vm2	3.11.8	Patched

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

High

Confidentiality

None

Integrity

Low

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Network

Privileges Req

Low

User Interaction

None

Every base score collected

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

Score	Version	Severity	Expl.	Impact	Source
7.1	CVSS 3.1	high	2.8	4.2	NVD, patriksimek (CNA), GHSA, Red Hat (VEX)
7.1	CVSS 4.0	high	—	—	patriksimek (CNA)

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-693 · Protection Mechanism Failure

Bypass Protection Mechanism::

Weakness & attack patterns

CWE-693

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

CAPEC-480 · Escaping VirtualizationCAPEC-237 · Escaping a Sandbox by Calling Signed Code in Another LanguageCAPEC-22 · Exploiting Trust in ClientCAPEC-20 · Encryption Brute ForcingCAPEC-36 · Using Unpublished InterfacesCAPEC-17 · Using Malicious FilesCAPEC-127 · Directory IndexingCAPEC-1 · Accessing Functionality Not Properly Constrained by ACLsCAPEC-107 · Cross Site TracingCAPEC-74 · Manipulating StateCAPEC-477 · Signature Spoofing by Mixing Signed and Unsigned ContentCAPEC-65 · Sniff Application Code

T1574.010Hijack Execution Flow: ServicesFile Permissions Weakness
T1083File and Directory Discovery
T1574.005Hijack Execution Flow: Executable Installer File Permissions Weakness

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

Detection

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

Prioritize edge telemetry for network-reachable vm2.
Monitor for scanner or exploit-pattern traffic after 1 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 7.1 (AV:N)
Sep 17, 2026 · NVD
Initial · CVE published
Sep 17, 2026 · NVD
Added · GHSA-9538-79j2-h62h published (high)
Sep 17, 2026 · GitHub Security Advisory
CVE published by MITRE.
Sep 17, 2026 · SOCRadar CTI

References

6 on the record

github.com/patriksimek/vm2/security/advisories/GHSA-f8gf-w286-fmq2
Exploit, Third Party Advisory, Mitre
www.vulncheck.com/advisories/vm2-before-3.11.8-allowasync-bypass-via-promise-thenable
Vendor Advisory, Mitre
nvd.nist.gov/vuln/detail/CVE-2026-92959
NVD
github.com/advisories/GHSA-9538-79j2-h62h
Exploit, Third Party Advisory
access.redhat.com/security/cve/CVE-2026-92959
Vendor Advisory
www.cve.org/CVERecord?id=CVE-2026-92959
Vendor Advisory

Elsewhere on this site

patriksimekevery CVE for this vendor
Unclassifiedsame class
CWE-693other pages naming this weakness

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.

Answered from this record1

What should defenders know first?

CVE-2026-92959 is vm2 before 3.11.8 allowAsync Bypass via Promise Thenable, a high vulnerability affecting vm2 from patriksimek. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-92959. Public exploit evidence is: 1 public PoC repositories reported; 0 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 7.1 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.