OpensshApplication · OpenBSD

CVE-2001-1459

HIGH · 7.5 CVSS v2.0 Published 2001-06-19
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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
OpenSSH 2.9 and earlier does not initiate a Pluggable Authentication Module (PAM) session if commands are executed with no pty, which allows local users to bypass resource limits (rlimits) set in pam.d.

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 confidence

OpenSSH 2.9 and earlier fails to initiate a PAM (Pluggable Authentication Module) session when commands are executed without a pseudo-terminal (pty), allowing local users to bypass resource limits (rlimits) configured in pam.d configuration files.

MitigationUpgrade to a patched version of OpenSSH that properly initiates PAM sessions for non-pty command executions, or implement alternative resource limit controls that are not dependent on PAM session initialization.

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
OpensshApplication
Affected:= 2.1= 2.1.1= 2.2= 2.3= 2.5= 2.5.1= 2.5.2= 2.9

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
Partial
Integrity
Partial
Availability
Partial

AV:N/AC:L/Au:N/C:P/I:P/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. Determine installed OpenSSH version
    Run 'sshd -v' or 'ssh -V' or check your package manager for the openssh version
    Affected if Version is 2.9 or earlier (2.1, 2.1.1, 2.2, 2.3, 2.5, 2.5.1, 2.5.2, or 2.9)
  2. Check if PAM is enabled in sshd_config
    Inspect /etc/ssh/sshd_config for the 'UsePAM' directive
    Affected if UsePAM is set to 'yes' and OpenSSH version is in the affected range
  3. Identify PAM configuration files with rlimit settings
    Review files in /etc/pam.d/ (particularly sshd or common-session) for 'ulimit' or 'rlimit' settings
    Affected if PAM configuration contains resource limit (ulimit/rlimit) settings that would be bypassed
  4. Audit for non-pty SSH command executions
    Review sshd logs and check for 'pty' allocation failures or command executions without pty allocation (look for sessions without 'session opened' PAM messages)
    Affected if There are log entries showing command execution without proper PAM session initialization

You are affected if you run OpenSSH 2.9 or earlier with PAM enabled (UsePAM yes) and have rlimits configured in pam.d that rely on session initialization for enforcement.

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

Upgrade to a patched version of OpenSSH that properly initiates PAM sessions for non-pty command executions, or implement alternative resource limit controls that are not dependent on PAM session initialization.

Fix this in Openssh Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing2.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,540
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2001-1459 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2001-1459 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
  • No spam, self-promotion, credentials, or personal data