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Reliant UnixOperating system · Siemens

CVE-2001-0411

MEDIUM · 5.0 CVSS v2.0 Published 2001-06-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

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 · unedited
Reliant Unix 5.44 and earlier allows remote attackers to cause a denial of service via an ICMP port unreachable packet, which causes Reliant to drop all connections to the source address of the packet.

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 · moderate confidence

Reliant Unix 5.44 and earlier contains a kernel-level flaw where processing of ICMP port unreachable packets causes the system to incorrectly drop ALL TCP/UDP connections from the packet's source address, rather than just the specific connection attempt. Remote attackers can exploit this by sending crafted ICMP port unreachable messages to cause a denial of service.

MitigationImplement network perimeter filtering to block or rate-limit ICMP unreachable packets from untrusted sources, or apply vendor-supplied kernel patches if available. Consider network segmentation to isolate affected systems.

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
Reliant UnixOperating system
Affected:= 5.44

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
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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the operating system
    Run 'uname -a' or 'uname -s' to determine the OS name
    Affected if The OS is not Reliant Unix (the vulnerability only affects Reliant Unix)
  2. Check the Reliant Unix version
    Run 'uname -r' or 'cat /etc/reliant' or check system documentation for the exact version number
    Affected if The version is 5.44 or any version earlier than 5.44 (e.g., 5.43, 5.42, etc.)
  3. Verify kernel configuration
    Review any custom kernel parameters related to ICMP handling in /etc/sysctl.conf or through the 'sysctl' command if applicable
    Affected if A custom kernel patch has not been applied - the default vulnerable kernel processes ICMP port unreachable packets incorrectly

If the system is running Siemens Reliant Unix version 5.44 or any earlier version without a vendor-supplied kernel patch, it is vulnerable to this ICMP-based denial of service flaw.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement network perimeter filtering to block or rate-limit ICMP unreachable packets from untrusted sources, or apply vendor-supplied kernel patches if available. Consider network segmentation to isolate affected systems.

Fix this in Reliant Unix Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,800
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2001-0411 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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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