CVE-1999-1559
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 · uneditedXylan OmniSwitch before 3.2.6 allows remote attackers to bypass the login prompt via a CTRL-D (control d) character, which locks other users out of the switch because it only supports one session at a time.
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 confidenceXylan OmniSwitch before version 3.2.6 contains an authentication bypass vulnerability where sending a CTRL-D character during the login prompt allows remote attackers to bypass the login prompt entirely, gaining unauthorized access to the switch management interface.
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<= 3.2.4CVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:N/A:P
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 the switch modelRun 'show system' or 'show version' command to confirm the device is a Xylan OmniSwitch or Alcatel OmniswitchAffected if The device is not an OmniSwitch product, then this CVE does not apply
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Check the software versionRun 'show version' or 'show system' to obtain the firmware/software version numberAffected if The version number is 3.2.4 or lower (e.g., 3.2.3, 3.2.2, 3.2.1, 3.2.0)
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Verify management interface accessibilityConfirm the switch has an IP address configured on the management interface (typically VLAN 1 or a dedicated management VLAN) and is reachable over the network via telnet or consoleAffected if The management interface is network-accessible (this is required for the remote attack vector)
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Check for CTRL-D handling in loginAttempt to connect to the device login prompt (via telnet or console) and observe if sending a CTRL-D character (0x04) bypasses authenticationAffected if CTRL-D bypasses the login prompt and grants access without credentials
You are affected if the device is an OmniSwitch running version 3.2.4 or lower and the management interface is network-accessible, allowing remote attackers to bypass login by sending CTRL-D.
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 dataUpgrade to Xylan OmniSwitch version 3.2.6 or later to obtain the patch. If upgrade is not feasible, restrict network access to the management interface via ACLs or place behind a jump host.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-1999-1559 — 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-1999-1559 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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