CVE-2016-7931
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 · uneditedThe MPLS parser in tcpdump before 4.9.0 has a buffer overflow in print-mpls.c:mpls_print().
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 confidenceA buffer overflow vulnerability exists in the MPLS (Multiprotocol Label Switching) parser of tcpdump before version 4.9.0. The overflow occurs in the mpls_print() function within print-mpls.c when processing malicious MPLS-labeled network packets. This critical flaw can potentially allow remote attackers to execute arbitrary code via specially crafted MPLS packets captured by tcpdump.
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<= 4.8.1CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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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Determine installed tcpdump versionRun 'tcpdump --version' or 'tcpdump -V' to display version informationAffected if Version displayed is 4.8.1 or earlier
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Verify MPLS support in tcpdump binaryRun 'tcpdump -v 2>&1 | grep -i mpls' or check compile-time flags with 'tcpdump -h' to see if MPLS decoding is availableAffected if MPLS support is present and the version is vulnerable
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Identify if live capture or pcap files process MPLS trafficReview capture scripts, cron jobs, or saved pcap files for MPLS-labeled packet capture; use 'tcpdump -i <iface> -v' and inspect for 'MPLS' in verbose outputAffected if tcpdump is actively processing or scheduled to process network traffic that may contain MPLS labels
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Check for tcpdump setuid or privileges on capture interfacesRun 'ls -la $(which tcpdump)' to see file permissions; check if tcpdump runs with elevated privileges for packet captureAffected if tcpdump has root privileges or setuid bit and processes network traffic containing MPLS labels
You are affected if tcpdump version is 4.8.1 or earlier AND the tool is used to process MPLS-labeled packets from live captures or pcap files.
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.
dbcve · scopedUpgrade tcpdump to version 4.9.0 or later. If immediate patching is not possible, restrict tcpdump's packet capture privileges and avoid analyzing untrusted network traffic until the update can be applied.
tcpdump 4.9.0 or later
- Check current tcpdump version: tcpdump --version
- Update your system's package repository to ensure you have access to the latest packages
- Upgrade tcpdump to version 4.9.0 or later using your system's package manager (e.g., apt-get update && apt-get install tcpdump for Debian/Ubuntu, yum update tcpdump for RHEL/CentOS, or emerge --ask net-analyzer/tcpdump for Gentoo)
- Verify the upgrade was successful by checking the version: tcpdump --version
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 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-2016-7931 — 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-2016-7931 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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- 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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