TcpdumpApplication

CVE-2017-5485

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 ISO CLNS parser in tcpdump before 4.9.0 has a buffer overflow in addrtoname.c:lookup_nsap().

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 tcpdump before 4.9.0 in the ISO CLNS (Connectionless Network Service) parser. The lookup_nsap() function in addrtoname.c fails to properly bounds-check when processing CLNS addresses, allowing overflow of a fixed-size buffer.

MitigationUpgrade tcpdump to version 4.9.0 or later. If immediate patching is not feasible, filter CLNS protocol traffic at network boundaries or disable CLNS packet dissection in tcpdump configurations.

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. Check if tcpdump is installed
    Run `tcpdump --version` or check via package manager (dpkg -l tcpdump, rpm -q tcpdump)
    Affected if tcpdump is present on the system
  2. Determine installed tcpdump version
    Parse the version number from the output of `tcpdump --version` and compare it to 4.9.0
    Affected if Version is 4.8.1 or lower
  3. Identify if CLNS/ISO traffic is being captured
    Review tcpdump capture scripts, snort rules, or network monitoring configurations for presence of CLNS, ISO, or IS-IS protocol keywords in capture filters
    Affected if tcpdump is actively processing or may process CLNS protocol traffic
  4. Check for CLNS packet dissection in tcpdump
    Inspect tcpdump configuration files or command-line options for CLNS-related flags or dissector settings (tcpdump -v, capture verbose output to observe protocol parsing)
    Affected if CLNS dissection or verbose protocol decoding is enabled and the affected tcpdump version is in use

A system is affected if it runs tcpdump version 4.8.1 or earlier AND the tool is processing or configured to process CLNS/ISO protocol traffic, enabling the buffer overflow in lookup_nsap().

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. If immediate patching is not feasible, filter CLNS protocol traffic at network boundaries or disable CLNS packet dissection in tcpdump configurations.

Recommended fix High confidence

tcpdump 4.9.0 or later

  1. 1. Identify the current tcpdump version by running 'tcpdump --version' or 'rpm -q tcpdump' / 'dpkg -l tcpdump'
  2. 2. Upgrade tcpdump to version 4.9.0 or later using your package manager (e.g., 'apt-get update && apt-get install tcpdump' or 'yum update tcpdump')
  3. 3. Verify the new version is installed by running 'tcpdump --version'
  4. 4. Test that tcpdump functions normally with your typical capture commands
  5. 5. Ensure any scripts or automation using tcpdump continue to work as expected

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
  • Testing3.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,570
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,512.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2017-5485 — 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-2017-5485 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