CVE-2026-61503
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 · uneditedRejetto HFS 3.0.0 through 3.2.0 returns observably different responses from its login endpoint depending on whether the submitted username exists. A remote unauthenticated attacker can use this to confirm valid account names, including the default admin account, facilitating password-guessing and session-forgery attacks.
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 confidenceRejetto HFS versions 3.0.0 through 3.2.0 contains a user enumeration vulnerability in its login endpoint. The server returns observably different HTTP responses (timing, content, or error messages) depending on whether a submitted username exists in the system. This allows unauthenticated remote attackers to confirm valid account names, including the default admin account, enabling subsequent password-guessing and session-forgery attacks.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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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Confirm HFS is running and accessibleCheck if the Rejetto HFS web interface is reachable by accessing the server IP/hostname on the configured port (typically 80 or 443). If the service is not exposed externally, verify locally via browser or curl to localhost.Affected if The HFS web interface is accessible and responding to requests.
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Identify the installed HFS versionAccess the HFS login page or check the server headers. The version is often displayed in the page footer or can be retrieved by examining the HTTP response headers. Compare the version number to the affected range 3.0.0 - 3.2.0.Affected if The installed version falls within 3.0.0 through 3.2.0.
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Test login endpoint for user enumerationSend two POST requests to the login endpoint (typically /~login or the root URL) with different usernames but the same password. Use a tool like curl or Burp Suite to capture the full response. Compare the HTTP status code, response body, and response time between the two requests.Affected if The server returns observably different responses (different error messages, timing, or status codes) depending on whether the username exists.
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Check for default admin accountSend a login POST request using the username 'admin' with any password. Observe whether the response differs from using a clearly non-existent username like 'nonexistentuser123'.Affected if The response for 'admin' is different from the response for a definitely invalid username, indicating the admin account exists and is enumerable.
A user is affected if HFS version 3.0.0-3.2.0 is running and the login endpoint returns different responses for existing versus non-existing usernames, allowing enumeration of valid accounts.
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.
From vendor dataNormalize all login endpoint responses to return identical content and timing regardless of username validity; implement rate limiting and account lockout policies to further impede enumeration attempts.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-61503 — 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-2026-61503 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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- Version or environment caveats, and links to real fixes
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