How severe is CVE-2026-87659?

CVE-2026-87659 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-87659 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-87659?

CVE-2026-87659 affects Broadcom Fabric Operating System. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-87659?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-87659 published?

CVE-2026-87659 was published on 2026-10-08 and last updated on 2026-10-13.

CVE-2026-87659

CVE-2026-87659 is a critical-severity vulnerability in Broadcom Fabric Operating System with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-306.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 7.1
EPSS exploit prediction: 0% (14th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Broadcom Fabric Operating System
Published: 2026-10-08
Last modified: 2026-10-13

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.

Frequently asked questions

What is CVE-2026-87659?: 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.
How severe is CVE-2026-87659?: CVE-2026-87659 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-87659 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-87659?: CVE-2026-87659 affects Broadcom Fabric Operating System. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-87659?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-87659 published?: CVE-2026-87659 was published on 2026-10-08 and last updated on 2026-10-13.

References

https://support.broadcom.com/external/content/SecurityAdvisories/0/39153

Affected products (1)

cpe:2.3:o:broadcom:fabric_operating_system:*:*:*:*:*:*:*:*

More vulnerabilities in Broadcom Fabric Operating System

CVE-2026-87684 — Critical (CVSS 9.8): A stack-based buffer overflow vulnerability exists in the SNMP daemon request handling of Brocade Fabric versions…
CVE-2022-33186 — Critical (CVSS 9.8): A vulnerability in Brocade Fabric OS software v9.1.1, v9.0.1e, v8.2.3c, v7.4.2j, and earlier versions could allow a…
CVE-2021-27797 — Critical (CVSS 9.8): Brocade Fabric OS before Brocade Fabric OS v8.2.1c, v8.1.2h, and all versions of Brocade Fabric OS v8.0.x and v7.x…
CVE-2020-15374 — Critical (CVSS 9.8): Rest API in Brocade Fabric OS v8.2.1 through v8.2.1d, and 8.2.2 versions before v8.2.2c is vulnerable to multiple…
CVE-2020-15373 — Critical (CVSS 9.8): Multiple buffer overflow vulnerabilities in REST API in Brocade Fabric OS versions v8.2.1 through v8.2.1d, and 8.2.2…
CVE-2020-15371 — Critical (CVSS 9.8): Brocade Fabric OS versions before Brocade Fabric OS v9.0.0, v8.2.2c, v8.2.1e, v8.1.2k, v8.2.0_CBN3, contains code…

All CVEs affecting Broadcom Fabric Operating System →

Other CWE-306 (Missing Authentication for Critical Function) vulnerabilities

CVE-2026-83938 — Critical (CVSS 10.0): Missing authentication for critical function in Azure Kubernetes Configuration Service allows an unauthorized attacker…
CVE-2026-105944 — Critical (CVSS 10.0): Apache Pulsar Manager is a web console for administering Apache Pulsar clusters. It has its own user accounts and…
CVE-2026-89309 — Critical (CVSS 10.0): The authorization middleware of the WMS MobileServer fails to require authentication in two distinct cases. First,…
CVE-2026-63692 — Critical (CVSS 10.0): Dell Container Storage Modules, versions prior to 1.18.0, contain(s) a Missing Authentication for Critical Function…
CVE-2026-63688 — Critical (CVSS 10.0): Dell Container Storage Modules (CSM), versions prior to v1.18.0, contains a Missing Authentication for Critical…
CVE-2026-103956 — Critical (CVSS 10.0): Missing authentication for critical function in the authentication dependency in Loom for AWS before 1.6.1 allowed…

Browse all CWE-306 (Missing Authentication for Critical Function) vulnerabilities →