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Debian LinuxOperating system · Debian

CVE-2017-5202

CRITICAL · 9.8 CVSS v3.0 Published 2017-01-28
Fix available
A fix is available. Upgrade to 4.9.0 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 print-isoclns.c:clnp_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 confidence

A buffer overflow vulnerability exists in the ISO CLNS (Connectionless Network Service) parser in tcpdump versions before 4.9.0. The flaw is located in the clnp_print() function in print-isoclns.c. When tcpdump processes specially crafted CLNS packets, it can overflow a buffer, potentially allowing remote code execution by an attacker sending malicious packets to a system running tcpdump.

MitigationUpgrade tcpdump to version 4.9.0 or later to patch this vulnerability. Until then, avoid processing untrusted CLNS/ISO network traffic with tcpdump and consider network segmentation to limit exposure to untrusted packet sources.

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
Debian LinuxOperating system
Affected:= 8.0= 9.0
Enterprise Linux DesktopOperating system
Affected:= 7.0
Enterprise Linux ServerOperating system
Affected:= 7.0
Enterprise Linux Server AusOperating system
Affected:= 7.4= 7.6
Enterprise Linux Server EusOperating system
Affected:= 7.4= 7.5= 7.6
Enterprise Linux Server TusOperating system
Affected:= 7.6
Enterprise Linux WorkstationOperating system
Affected:= 7.0
TcpdumpApplication
Affected:< 4.9.0

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' on Linux or check the package manager (dpkg -l | grep tcpdump for Debian/Ubuntu, rpm -qa | grep tcpdump for RHEL/CentOS)
    Affected if tcpdump is not found on the system, then it is not affected
  2. Determine installed tcpdump version
    Run 'tcpdump --version' or 'tcpdump -h' to display version information. For RPM-based systems use 'rpm -q tcpdump'. For Debian-based systems use 'dpkg -s tcpdump'
    Affected if the version displayed is less than 4.9.0, the system is potentially affected
  3. Confirm version matches affected distribution packages
    Check that the installed version corresponds to the listed vulnerable versions for Debian 8/9 or RHEL 7.x
    Affected if the installed version is Debian 8.0, Debian 9.0, RHEL 7.0, RHEL 7.4, RHEL 7.5, or RHEL 7.6, it is within the affected range

If tcpdump version is installed and the version is below 4.9.0, the environment is vulnerable to this buffer overflow when processing CLNS 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 4.9.0 or later
Fixed in 4.9.0
Interim mitigation

Upgrade tcpdump to version 4.9.0 or later to patch this vulnerability. Until then, avoid processing untrusted CLNS/ISO network traffic with tcpdump and consider network segmentation to limit exposure to untrusted packet sources.

Recommended fix High confidence

tcpdump 4.9.0

  1. Update your package repository index: 'apt-get update' (Debian) or 'yum update' or 'dnf update' (RHEL/CentOS)
  2. Upgrade tcpdump to the latest available version: 'apt-get install tcpdump' (Debian) or 'yum update tcpdump' or 'dnf update tcpdump' (RHEL/CentOS)
  3. Verify the installed version is 4.9.0 or later: 'tcpdump --version'
  4. Confirm the fix resolves the issue by checking that the clnp_print function no longer has the buffer overflow vulnerability
Caveat Upgrading tcpdump is typically low-risk; however, verify any custom scripts or wrappers that parse tcpdump output for compatibility with the new version

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

Fix this in Debian Linux 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
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

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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-2017-5202 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