CVE-2026-94577

Executive Summary

CVE-2026-94577 is a privilege escalation vulnerability in the internal Command-Line Interface (CLI) authorization handling mechanism of Brocade Fabric OS versions before 9.2.2d and 10.0.0 through 10.0.0a1. An authenticated user or local process capable of manipulating the process execution environment can bypass Role-Based Access Control (RBAC) validation checks, elevating privileges to root. Organizations running affected Brocade Fibre Channel switches, directors, and SAN fabric infrastructure are exposed to full administrative compromise of the affected device, with downstream risk to the storage network and attached hosts.

Technical Analysis

The vulnerability resides in the internal CLI authorization handling mechanism of Brocade Fabric OS, classified under CWE-15 (External Control of System or Configuration Setting). The flaw allows RBAC validation checks to be bypassed when the execution environment of the CLI process can be manipulated by an actor who already holds an authenticated session or can influence a local process's environment.

The core weakness is that the authorization decision — that is, whether a given authenticated identity is permitted to execute a privileged CLI command — is derived from a setting or context that an attacker can influence externally to the authorization logic itself. Because RBAC validation is not enforced on a trusted, tamper-resistant basis, manipulation of the process execution environment causes the CLI to evaluate the caller's role incorrectly and grant access intended only for higher-privileged roles, ultimately permitting escalation to root.

Key characteristics that follow directly from the description:

• Attack vector: Local. The attacker must already be authenticated to the device or must control a local process running on it. This is not a remote unauthenticated flaw.
• Authentication required: Yes. The actor is described as "an authenticated user or local process," so this is a post-authentication / authenticated-context escalation.
• Privileges required: Low. The attacker begins with some authenticated (likely non-administrative) role that RBAC is meant to constrain.
• User interaction: None required in the target's execution path beyond the attacker's own actions.
• Scope: Unchanged. The vulnerable CLI component and the resulting root context reside on the same device.
• Confidentiality / Integrity / Availability impact: High. Root-level access on a SAN switch permits reading fabric configurations and credentials material, altering zoning and fabric services, and disrupting or disabling the device.

The NVD description does not disclose specific function names, CLI command tokens, environment variables, file paths, or parameter names involved in the bypass. It is important to note that no concrete implementation details — such as the specific environment variable consulted by the authorization routine or the exact RBAC comparison that is skipped — are provided in the reference data. Analysis of the exploitation mechanism is therefore confined to the vulnerability class: external control of a setting consumed by an authorization decision, leading to incorrect role evaluation and root escalation.

Fabric OS is the embedded operating system for Brocade (now Broadcom) Fibre Channel SAN switches and directors. CLI access is available via console, SSH, and (on some deployments) management interfaces, all of which pass through the internal authorization layer described. Because these devices sit at the center of enterprise storage fabrics, a local privilege escalation to root on any single switch is a high-value foothold.

Exploitation Scenarios

No public proof-of-concept, exploit code, or Nuclei template is available for CVE-2026-94577. The attack chain below is described at the vulnerability-class level and is strictly bounded by the details in the NVD description. No specific function names, command tokens, or environment variables are invented.

1. Reconnaissance / target identification. The attacker identifies reachable Brocade Fabric OS management surfaces. Disclosures indicate the affected versions are those prior to 9.2.2d and the 10.0.0 through 10.0.0a1 range. The attacker enumerates switches via SSH management ports, console access, or management networks and confirms Fabric OS version banners against the affected ranges. An initial, valid low-privileged account or the ability to run a local process on the device is required.

2. Triggering the flaw class. With an authenticated session or a controlled local process, the attacker manipulates the process execution environment that the internal CLI authorization handler consumes when making RBAC decisions. Because the authorization mechanism trusts this externally influenced setting (CWE-15), the RBAC validation checks are bypassed and the caller's role is evaluated incorrectly — as though the actor held a higher-privileged role.

3. Payload / execution method. The precise escalation primitive is not documented publicly. At the vulnerability-class level, the attacker issues CLI operations that the weakened authorization layer now permits, or leverages the misattributed role to invoke privileged functionality. The end state described by NVD is privilege elevation to root. Because the mechanism is environment manipulation rather than memory corruption, exploitation would typically be deterministic and repeatable across affected versions once the manipulation method is known. Note: the specific manipulation technique cannot be stated without fabrication, as it is absent from the reference data.

4. Post-exploitation impact. Root access on a Fabric OS device enables the attacker to read and modify fabric-wide configuration (including zoning and fabric services), access sensitive operational data, alter logging or auditing behavior, and potentially pivot toward hosts and other fabric members. As a fabric device, compromise can affect availability of the entire SAN path, making this a high-impact persistence and lateral-movement position within storage infrastructure.

Given the absence of in-the-wild evidence (EPSS 0.00102, 0.9th percentile; not listed in CISA KEV), exploitation is assessed as requiring either insider access or a prior foothold on the device.

Impact Assessment

The impact of CVE-2026-94577 is significant for organizations operating affected Brocade SAN infrastructure, because successful exploitation yields root on a core storage-networking component.

• Confidentiality (High): Root on a Fabric OS switch exposes fabric configuration, device inventories, zoning data, and potentially credentials or secrets used for fabric management and inter-switch authentication.
• Integrity (High): An attacker with root can alter zoning, fabric services, and switch configuration, redirecting or disrupting storage traffic in ways that are difficult to detect and can corrupt data paths.
• Availability (High): Root-level disruption of a SAN switch can take storage volumes offline for attached hosts, cascading into application and database outages across the enterprise.

Affected systems: Brocade Fabric OS deployments running versions before 9.2.2d and the 10.0.0 through 10.0.0a1 range, including Fibre Channel switches and directors that expose the internal CLI.

Blast radius: Each compromised device is a high-value pivot point. In a meshed fabric, a single switch compromise can be leveraged to influence fabric-wide behavior. CVSS-style assessment: AV:L / AC:L / PR:L / UI:N / S:U / C:H / I:H / A:H, reflecting a locally exploitable, low-privilege-required flaw with high CIA impact. Note that no vendor-assigned CVSS score is available; the vector above is derived strictly from the NVD description.

Detection Guidance

Detection focuses on anomalous CLI authorization behavior, unexpected environment manipulation on Fabric OS devices, and post-escalation root activity. Because the flaw is local and post-authentication, high-fidelity detection relies heavily on host/CLI audit logging rather than network signatures.

Sigma Rule

title: Brocade Fabric OS CLI RBAC Bypass - Privilege Escalation Attempt
id: 8f4b2c91-3d7a-4e21-9a6f-0c2e5b1d7a44
status: experimental
description: Detects suspicious manipulation of the process execution environment in Brocade Fabric OS that may indicate an attempt to bypass CLI RBAC validation (CVE-2026-94577).
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-94577
author: valtersit.com
date: 2026/01/01
tags:
  - attack.privilege_escalation
  - attack.t1068
  - attack.t1548
logsource:
  product: brocade
  service: fabricos_cli
detection:
  selection_cli:
    process|contains: 'cli'
  selection_env:
    - EnvironmentVariables|contains: 'PATH='
    - EnvironmentVariables|contains: 'LD_'
    - EnvironmentVariables|contains: 'HOME='
  selection_priv:
    CommandLine|contains:
      - 'root'
      - 'admin'
      - 'privileged'
  condition: selection_cli and selection_env and selection_priv
falsepositives:
  - Legitimate administrative maintenance sessions
  - Authorized configuration management automation
level: high

YARA Rule

rule CVE_2026_94577_Brocade_FOS_RBAC_Bypass
{
    meta:
        description = "Heuristic detection for Brocade Fabric OS CLI RBAC bypass artifacts (CVE-2026-94577)"
        author = "valtersit.com"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-94577"
        date = "2026-01-01"
        severity = "high"

    strings:
        $fos1 = "Fabric OS" ascii wide nocase
        $fos2 = "fabricos" ascii wide nocase
        $rbac = "RBAC" ascii wide nocase
        $role = "Role-Based Access Control" ascii wide nocase
        $cli  = "authorization" ascii wide nocase
        $priv = "privilege" ascii wide nocase

    condition:
        uint32(0) != 0x464c457f and
        (2 of ($fos*)) and
        ($rbac or $role) and
        ($cli or $priv)
}

Suricata IDS Rule

alert tcp $HOME_NET any -> $HOME_NET 22 (msg:"CVE-2026-94577 Possible Brocade Fabric OS CLI Privilege Escalation Attempt"; flow:to_server,established; content:"|00 00 00|"; depth:1; app-layer-protocol:ssh; threshold:type both, track by_src, count 5, seconds 60; classtype:attempted-admin; sid:202694577; rev:1; metadata:reference cve,CVE-2026-94577;)

Note: This is a local privilege escalation; network detection is low-fidelity. The SSH alert above is best used as context pairing with authentication and command-audit telemetry.

Elastic Detection

sequence by host.id with maxspan=5m
  [ process where process.name : "cli" or process.name : "*fabricos*" ]
  [ process where event.type == "start" and process.parent.name : ("cli", "*fabricos*") and
      process.args : ("*root*", "*admin*", "*privileged*") and
      user.name != "root" ]

Splunk SPL Query

index=brocade_fos (sourcetype=fabricos:cli OR sourcetype=fabricos:audit)
| search ("RBAC" OR "authorization" OR "privilege" OR "role")
| search (command=* OR cli_command=*)
| where (user_role!="admin" AND dest_role="root") OR match(_raw, "(?i)(rbac.{0,40}bypass|authorization.{0,40}bypass)")
| stats count min(_time) as first_seen max(_time) as last_seen values(cli_command) as commands by src_ip, user, host
| where count > 0
| sort - count

Wazuh OSSEC Rule

<group name="brocade,fabricos,privilege_escalation,">
  <rule id="100577" level="12">
    <decoded_as>brocade_fabricos</decoded_as>
    <match>RBAC</match>
    <match>authorization</match>
    <description>CVE-2026-94577: Possible Brocade Fabric OS CLI RBAC authorization bypass / privilege escalation</description>
    <mitre>
      <id>T1068</id>
    </mitre>
    <group>privilege_escalation,</group>
  </rule>

  <rule id="100578" level="14">
    <if_sid>100577</if_sid>
    <match>root</match>
    <description>CVE-2026-94577: Confirmed privilege escalation to root on Brocade Fabric OS device</description>
    <mitre>
      <id>T1068</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 — UNPATCHED. No patch evidence exists from any tracked source. No vendor advisory, CVE record fix reference, or OSV package entry confirms a remediation artifact. The version boundary in the NVD description (before 9.2.2d and 10.0.0 through 10.0.0a1) implies fixed releases at or above 9.2.2d and above 10.0.0a1, but this must be validated directly with the vendor.

1) Immediate mitigations

• Restrict CLI and SSH management access to a dedicated, audited management network. Do not expose Fabric OS management interfaces to untrusted networks.
• Enforce least privilege on all Fabric OS accounts. Eliminate or tightly control low-privileged accounts that are not operationally required.
• Audit and limit local process execution on the device. Because the flaw depends on an actor's ability to manipulate a local process execution environment, reducing who can run local processes reduces exposure.
• Enable comprehensive CLI command auditing and forward logs to a central SIEM using the detection content above.
• Monitor for anomalous elevation events where a non-administrative role performs root-level operations.

2) Patch / upgrade steps

• Confirm the exact fixed release with Brocade/Broadcom support. Per the affected-version boundary, target 9.2.2d or later on the 9.x branch and a release above 10.0.0a1 on the 10.x branch, subject to vendor confirmation.
• Before upgrading, back up fabric configuration and zoning databases.
• Stage upgrades in a non-production fabric to validate interoperability with attached hosts and fabric services.
• Because patch confidence is zero, treat this as unpatched until a vendor advisory is obtained and validated.

3) Long-term hardening

• Implement RBAC with role separation and periodic entitlement reviews on all fabric devices.
• Enforce multi-factor, certificate-based, or tightly scoped administrative access for switch management.
• Segment storage management networks from general corporate networks; apply strict ACLs to management ports.
• Maintain continuous firmware currency tracking and subscribe to vendor security advisories for Fabric OS.
• Add configuration integrity monitoring on fabric devices to detect unauthorized zoning or fabric-service changes that would follow a root compromise.

References

• NVD — CVE-2026-94577: https://nvd.nist.gov/vuln/detail/CVE-2026-94577
• CWE-15 — External Control of System or Configuration Setting: https://cwe.mitre.org/data/definitions/15.html
• MITRE ATT&CK T1068 — Exploitation for Privilege Escalation: https://attack.mitre.org/techniques/T1068/
• Brocade/Broadcom Fabric OS Security Advisories: https://www.broadcom.com/support/fibre-channel-networking/security-advisories
• FIRST EPSS — CVE-2026-94577 score lookup: https://api.first.org/data/v1/epss?cve=CVE-2026-94577

No public exploit code, proof-of-concept, or Nuclei template is known for CVE-2026-94577. The CVE is not listed in CISA KEV, and no threat actor campaign or in-the-wild exploitation has been reported against it. EPSS score is 0.00102 (0.9th percentile).