CVE-2018-19637
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 · uneditedSupportutils, before version 3.1-5.7.1, wrote data to static file /tmp/supp_log, allowing local attackers to overwrite files on systems without symlink protection
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 confidenceSupportutils before version 3.1-5.7.1 writes output to a static file at /tmp/supp_log without checking for existing symlinks, allowing a local attacker to create a symlink at that path pointing to a sensitive file (e.g., /etc/passwd). When supportutils runs, it follows the symlink and overwrites the target file, enabling local privilege escalation or data destruction on systems lacking symlink protection in /tmp.
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< 3.1-5.7.1CVSS 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
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
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 supportutils is installedRun: rpm -q supportutils (on RPM-based systems) or dpkg -l supportutils (on Debian-based systems)Affected if If the package is not installed, the system is not affected by this specific vulnerability
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Determine the installed version of supportutilsRun: rpm -q --qf '%{VERSION}-%{RELEASE}' supportutils or rpm -qi supportutils to see version detailsAffected if If the installed version is lower than 3.1-5.7.1, the system is vulnerable to symlink attacks
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Check if a symlink already exists at /tmp/supp_logRun: ls -la /tmp/supp_log to see if the file is a symlinkAffected if If /tmp/supp_log points to a sensitive file (such as /etc/passwd or /etc/shadow), exploitation has occurred or is imminent
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Verify /tmp mount options for symlink protectionRun: mount | grep ' /tmp ' to check if nosymfollow option is presentAffected if If nosymfollow is NOT present and supportutils version is below 3.1-5.7.1, the system lacks the compensating control
The system is affected if supportutils version is below 3.1-5.7.1 AND the /tmp filesystem lacks nosymfollow protection, allowing symlink attacks on the /tmp/supp_log file.
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 data3.1-5.7.1
Upgrade to supportutils version 3.1-5.7.1 or later, which implements secure temporary file handling with symlink checks. As a compensating control, enable symlink protection in the /tmp mount options (nosymfollow) if not already enabled.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-19637 — 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-2018-19637 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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