CVE-2008-5138
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 · uneditedpasswdehd in libpam-mount 0.43 allows local users to overwrite arbitrary files via a symlink attack on a /tmp/passwdehd.##### temporary file.
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 confidenceThis is a symlink attack vulnerability in the passwdehd utility of libpam-mount version 0.43. The program creates temporary files in /tmp with predictable names (passwdehd.#####), allowing local unprivileged users to pre-create symlinks with matching names. When passwdehd runs (typically with elevated privileges as it's part of PAM), it follows the symlink and writes to an attacker-controlled location, enabling arbitrary file overwrite.
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= 0.43CVSS 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
- Local
- Complexity
- M
- Authentication
- None
- Confidentiality
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:L/AC:M/Au:N/C:C/I:C/A:C
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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Check if libpam-mount is installedRun 'dpkg -l libpam-mount' or 'rpm -qa | grep -i libpam-mount' or 'ls -la /usr/bin/pmount' to see if the package is presentAffected if The package is installed and version is 0.43 exactly, or if a version cannot be determined but the package exists on a system where the passwdehd utility runs with elevated privileges
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Identify the installed version of libpam-mountRun 'dpkg -s libpam-mount 2>/dev/null | grep Version' or 'rpm -q libpam-mount' to retrieve the exact version numberAffected if The version returned is 0.43 (note: the '=' in the advisory indicates only version 0.43 is affected)
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Locate the passwdehd utilityRun 'which passwdehd' or 'find /usr -name passwdehd -type f' to find the binaryAffected if The passwdehd binary exists on the system (the vulnerability lies in its temporary file creation in /tmp)
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Check if PAM services use pam-mountInspect PAM configuration files in /etc/pam.d/ for entries containing 'pam_mount.so' using 'grep -r pam_mount /etc/pam.d/'Affected if Any service (login, sshd, su, etc.) is configured to use pam_mount, meaning passwdehd may execute with elevated privileges during authentication
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Verify temp file creation behavior of passwdehdObserve /tmp for files matching pattern 'passwdehd.*****' during authentication or service restart; use 'ls -la /tmp/passwdehd*' to check for existing predictable temp filesAffected if Files with predictable names matching passwdehd.##### pattern exist or can be created, confirming the vulnerable behavior
A system is affected if libpam-mount version 0.43 is installed AND pam_mount is configured in any PAM service, as this enables the passwdehd utility to run with elevated privileges and follow attacker-controlled symlinks in /tmp.
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 a patched version of libpam-mount that implements secure temporary file creation using mkstemp() or the O_EXCL flag to prevent symlink race conditions.
- Consultation1.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2008-5138 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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