CVE-2017-5486 Tcpdump CVE debrief

Who should care

Security teams running tcpdump on production hosts, packet capture appliances, analysis pipelines, and Linux distributions that package tcpdump 4.8.1 or earlier should prioritize this issue. It is especially relevant where tcpdump may process untrusted network traffic or packet captures.

Technical summary

The flaw is a buffer overflow in the ISO CLNS parsing path of tcpdump, with the vulnerable function identified as clnp_print() in print-isoclns.c. The CVE description places the issue in tcpdump before 4.9.0, while NVD’s CPE data marks tcpdump up to and including 4.8.1 as vulnerable and classifies the weakness as CWE-119.

Defensive priority

High. This is a critical memory-safety issue in a widely used packet analysis tool, with NVD assigning CVSS 9.8 and a network-based attack vector. Patch or replace affected builds promptly, especially on systems that analyze untrusted traffic or captures.

Recommended defensive actions

• Upgrade tcpdump to 4.9.0 or a vendor package that includes the fix.
• Inventory systems and images for tcpdump 4.8.1 and earlier, including embedded and offline analysis environments.
• Review distribution advisories and errata for package-specific remediation from Debian, Red Hat, and Gentoo.
• Limit tcpdump use on untrusted input until patched, and restrict who can run packet capture/analysis jobs.
• Validate that any backported security update in your distro actually includes the tcpdump fix rather than only a version string change.

Evidence notes

The CVE description states that the ISO CLNS parser in tcpdump before 4.9.0 has a buffer overflow in print-isoclns.c:clnp_print(). NVD metadata supplies the affected CPE range (tcpdump through 4.8.1), CVSS 3.0 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), and CWE-119 classification. The supplied references include Debian, Red Hat, and Gentoo advisories/errata, indicating ecosystem remediation activity. No KEV entry was supplied for this CVE.

Official resources