CVE-2025-6391
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBrocade 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceBrocade ASCG before version 3.3.0 improperly logs JSON Web Tokens (JWT) in plaintext to log files. An attacker with access to these log files can extract the unencrypted tokens and use them for session hijacking, unauthorized access, or information disclosure.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 3.2.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify installed Brocade ASCG versionLocate and examine the installed Brocade Active Support Connectivity Gateway version on the system using the product's version lookup mechanism or administrative interfaceAffected if The version is 3.2.0 or earlier (versions before 3.3.0 are affected)
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Confirm logging is enabledCheck whether the logging functionality is active on the ASCG instance, as the vulnerability only manifests when JWT tokens are written to log filesAffected if Logging is enabled and the version is 3.2.0 or earlier
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Locate log filesIdentify the directory or directories where ASCG stores its log files, typically found in the product's logging or system log locationsAffected if Log files exist and are accessible to the attacker (any user with read access to logs)
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Search log files for JWT tokensExamine the identified log files for plaintext JWT token patterns (tokens typically appear as three base64-encoded sections separated by dots, such as eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...)Affected if JWT tokens are found in plaintext within any log file
A system is affected if it runs Brocade ASCG version 3.2.0 or earlier AND has logging enabled, with plaintext JWT tokens present in accessible log files indicating the vulnerability is present.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade Brocade ASCG to version 3.3.0 or later, and rotate any JWTs that may have been logged prior to the update.
Brocade Active Support Connectivity Gateway 3.3.0
- Check current Brocade ASCG version using the administrative interface or CLI command
- Backup the current ASCG configuration according to vendor backup procedures
- Download Brocade ASCG version 3.3.0 or later from support.broadcom.com
- Apply the upgrade following the official upgrade documentation from Broadcom
- After upgrade, verify the version has been updated to 3.3.0 or later
- Review log files to confirm JWT tokens are no longer being written to logs
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-6391 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-6391 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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