Vulnerability · Published Oct 2, 2026 · Assigned by VulnCheck

CVE-2026-82042UTMStack < 11.2.16 Authentication Bypass via InternalApiKeyFilter

Critical 9.8

In plain English

A critical-severity missing authentication in UTMStack from UTMStack. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities).

Severity (CVSS 3.1)9.8Critical

Exploit odds (30 days)0.5%top 54.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

UTMStack before 11.2.16 contains an authentication bypass vulnerability that allows remote attackers to gain full administrative API access by presenting a valid Utm-Internal-Key header matching the INTERNAL_KEY environment variable value, which the InternalApiKeyFilter accepts for any endpoint without path restriction, constant-time comparison, rate limiting, or audit logging. Attackers who obtain the key value can authenticate without a user account or JWT to create accounts, manage users, exfiltrate data, and modify security rules.

Affected products (as reported)

Vendor	Product	Versions
UTMStack	UTMStack	0 – before 11.2.16

Weakness: CWE-306 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

UTMStack v11.2.16 Release Notes release-notes
Patch Commit patch
https://www.vulncheck.com/advisories/utmstack-authentication-bypass-via-internalapikeyfilter third-party-advisory