CVE-2026-33217

Description

A flaw was found in NATS-Server. When Access Control Lists (ACLs) were configured for message subjects, these controls were not correctly applied within the $MQTT.> namespace. This oversight allows MQTT clients to bypass the intended ACL checks, potentially granting unauthorized access to sensitive message subjects. This vulnerability could lead to information disclosure or unauthorized message manipulation.

Mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Common Vulnerability Scoring System (CVSS) Score Details

Info alert:Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score8.16.58.1
Attack VectorNetworkNetworkNetwork
Attack ComplexityLowLowLow
Privileges RequiredLowNoneLow
User InteractionNoneNoneNone
ScopeUnchangedUnchangedUnchanged
ConfidentialityHighLowHigh
Integrity ImpactHighLowHigh
Availability ImpactNoneNoneNone

Vector

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

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

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

Understanding the Weakness (CWE)

CWE-425

Confidentiality,Integrity,Availability,Access Control

Technical Impact: Read Application Data; Modify Application Data; Execute Unauthorized Code or Commands; Gain Privileges or Assume Identity

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