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AixOperating system · Ibm

CVE-2001-1554

MEDIUM · 5.0 CVSS v2.0 Published 2001-12-31
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
IBM AIX 430 does not properly unlock IPPMTU_LOCK, which allows remote attackers to cause a denial of service (hang) via Path Maximum Transmit Unit (PMTU) IP packets.

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

IBM AIX 430 contains a kernel-level locking bug where the IPPMTU_LOCK is not properly released after Path Maximum Transmit Unit (PMTU) IP packet processing. When malformed or specific PMTU packets are received remotely, the lock remains held, causing the system to hang due to the unreleased mutex.

MitigationApply the IBM AIX patch for this vulnerability or upgrade to a fixed AIX version. If patching is not immediately feasible, consider firewall rules to limit exposure of affected systems to untrusted networks.

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
AixOperating system
Affected:= 430

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. Confirm AIX version is 430
    Run 'oslevel -r' or check /etc/AIX for the installed version to verify it matches exactly version 430
    Affected if The installed AIX version is 430 (any subversion) since only this specific version is affected
  2. Determine if the system has network exposure
    Review network interfaces and firewall rules to assess whether the system can receive remote IP packets from untrusted networks
    Affected if The system is directly accessible from untrusted networks, as the exploit is triggered by receiving malformed PMTU packets remotely
  3. Check if IP PMTU processing is active
    Verify that IP Path MTU Discovery (PMTU) is enabled on the system - this is typically active by default in AIX network stacks
    Affected if IP PMTU processing is enabled (which is the default configuration), as the vulnerability exists in this code path

A system is affected if it is running AIX version 430 with network accessibility and IP PMTU processing enabled, as the kernel lock bug is triggered by remote malformed PMTU packets causing a hang.

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

Apply the IBM AIX patch for this vulnerability or upgrade to a fixed AIX version. If patching is not immediately feasible, consider firewall rules to limit exposure of affected systems to untrusted networks.

Fix this in Aix Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
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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-2001-1554 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
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