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TcpdumpApplication

CVE-2016-7973

CRITICAL · 9.8 CVSS v3.0 Published 2017-01-28
Fix available
A fix is available. Upgrade to after 4.8.1 or later.
See remediation →
100/100
Remediation priority · Urgent
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
The AppleTalk parser in tcpdump before 4.9.0 has a buffer overflow in print-atalk.c, multiple functions.

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

A buffer overflow vulnerability exists in the AppleTalk parser (print-atalk.c) of tcpdump versions before 4.9.0, affecting multiple functions within the parser. The flaw has a CVSS score of 9.8 (CRITICAL), indicating potential for remote code execution or denial of service via specially crafted AppleTalk packets.

MitigationUpgrade tcpdump to version 4.9.0 or later to remediate the buffer overflow in the AppleTalk parser. If upgrading is not immediately feasible, restrict network access to systems running tcpdump and disable AppleTalk protocol parsing if not required.

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
TcpdumpApplication
Affected:<= 4.8.1

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
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 checks

Work through these to decide whether this CVE applies to you.

  1. Verify tcpdump is installed
    Run 'which tcpdump' or 'tcpdump --version' to locate the binary and confirm it exists on the system
    Affected if tcpdump is not installed or the command returns an error, the system is not affected by this specific vulnerability
  2. Determine installed tcpdump version
    Run 'tcpdump --version' and examine the output for the version number (e.g., 4.8.1, 4.7.4, etc.)
    Affected if The version is 4.8.1 or lower, indicating the vulnerable version is installed
  3. Check if AppleTalk parsing is in use
    Review any tcpdump capture scripts, cron jobs, or ongoing processes that use tcpdump. Look for command-line usage that includes AppleTalk-related filters (e.g., 'atalk' keyword) or examine packet capture logs for AppleTalk protocol data
    Affected if tcpdump is actively parsing AppleTalk traffic or AppleTalk packets are being captured and decoded
  4. Verify the vulnerable parser component exists
    If tcpdump source code is available, confirm print-atalk.c exists in the source tree. For binary installations, cross-reference the tcpdump version with the known vulnerable release (4.8.1 and below)
    Affected if The installed tcpdump binary was built from source versions 4.8.1 or earlier containing the print-atalk.c parser component

A system is affected if tcpdump version 4.8.1 or lower is installed and tcpdump is or may be used to capture or analyze network traffic that could contain AppleTalk packets.

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.

dbcve · scoped
Upgrade available Upgrade to a release after 4.8.1
Interim mitigation

Upgrade tcpdump to version 4.9.0 or later to remediate the buffer overflow in the AppleTalk parser. If upgrading is not immediately feasible, restrict network access to systems running tcpdump and disable AppleTalk protocol parsing if not required.

Recommended fix High confidence

tcpdump 4.9.0 or later

  1. Check current tcpdump version: tcpdump --version or dpkg -l | grep tcpdump (Debian) / rpm -q tcpdump (RHEL)
  2. Upgrade tcpdump to version 4.9.0 or later using your package manager: apt-get update && apt-get install tcpdump (Debian/Ubuntu) or yum update tcpdump (RHEL/CentOS)
  3. If the package is not available in your distribution repository, download tcpdump 4.9.0 or later from www.tcpdump.org and compile from source: ./configure && make && make install
  4. Verify the installation: tcpdump --version
Caveat Minor: tcpdump output format may differ slightly due to parser changes; ensure any parsing scripts accommodate potential format variations

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Tcpdump Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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Scan for this in your stack

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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-2016-7973 in production — separate from our analysis above.

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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