How severe is CVE-2025-6391?

CVE-2025-6391 has a CVSS 3.x base score of 9.1, 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 none.

Is CVE-2025-6391 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-6391?

CVE-2025-6391 affects Broadcom Brocade Active Support Connectivity Gateway. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-6391?

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.

Does CVE-2025-6391 have an EU (EUVD) identifier?

Yes. CVE-2025-6391 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21828.

When was CVE-2025-6391 published?

CVE-2025-6391 was published on 2025-07-17 and last updated on 2026-06-17.

CVE-2025-6391

CVE-2025-6391 is a critical-severity vulnerability in Broadcom Brocade Active Support Connectivity Gateway with a CVSS 3.x base score of 9.1. 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-532.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v4: 7.1
EPSS exploit prediction: 0% (15th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-21828
Weakness: CWE-532
Affected product: Broadcom Brocade Active Support Connectivity Gateway
Published: 2025-07-17
Last modified: 2026-06-17

Description

Brocade ASCG before 3.3.0 logs JSON Web Tokens (JWT) in log files. An attacker with access to the log files can withdraw the unencrypted tokens with security implications, such as unauthorized access, session hijacking, and information disclosure.

Frequently asked questions

What is CVE-2025-6391?: Brocade ASCG before 3.3.0 logs JSON Web Tokens (JWT) in log files. An attacker with access to the log files can withdraw the unencrypted tokens with security implications, such as unauthorized access, session hijacking, and information disclosure.
How severe is CVE-2025-6391?: CVE-2025-6391 has a CVSS 3.x base score of 9.1, 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 none.
Is CVE-2025-6391 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-6391?: CVE-2025-6391 affects Broadcom Brocade Active Support Connectivity Gateway. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-6391?: 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.
Does CVE-2025-6391 have an EU (EUVD) identifier?: Yes. CVE-2025-6391 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21828.
When was CVE-2025-6391 published?: CVE-2025-6391 was published on 2025-07-17 and last updated on 2026-06-17.

References

https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/35951

Affected products (1)

cpe:2.3:a:broadcom:brocade_active_support_connectivity_gateway:*:*:*:*:*:*:*:*

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