How severe is CVE-2026-87659?

No CVSS score has been assigned to CVE-2026-87659 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-87659?

Affected package information for CVE-2026-87659 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2026-87659?

No fixed release is recorded for CVE-2026-87659 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

How do I detect CVE-2026-87659 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2026-87659 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-87659 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-87659 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-87659?

CVE-2026-87659 has an EPSS (Exploit Prediction Scoring System) score of 0.1%, placing it in the 3th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-87659?

CVE-2026-87659 is classified as Missing Authentication (CWE-306). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-87659 published, and has it been updated?

CVE-2026-87659 was published on October 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-87659: Missing Authentication

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-87659.

EPSS Exploitation Probability

via FIRST.org ↗

0.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs3th percentile — riskier than 3% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Description

A critical authorization bypass vulnerability exists in the Management Server handling of Brocade Fabric OS versions before 10.0.1. A compromised switch connected to the fabric can transmit crafted inband Fibre Channel vendor-unique CT (Common Transport) management requests to bypass administrative authentication. Successful exploitation allows an unauthorized peer switch to execute administrative actions on the target device, including resetting administrative passwords, initiating system reboots, and triggering firmware downloads.

Affected Products

1 product · 1 configurations

OS

fabric operating systembroadcom

< 10.0.1

range

Detection & mitigation playbook

Vulnerability

Detect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2026-87659 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

A critical authorization bypass vulnerability exists in the Management Server handling of Brocade Fabric OS versions before 10.0.1. A compromised switch connected to the fabric can transmit crafted inband Fibre Channel vendor-unique CT (Common Transport) management requests to bypass administrative authentication. Successful exploitation allows an unauthorized peer switch to execute administrative actions on the target device, including resetting administrative passwords, initiating system reboots, and triggering firmware downloads.

O3 Security · Impact-Aware SCA

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CVE-2026-87659