# CVE-2017-5204: tcpdump buffer overflow in IPv6 parser

Source: https://junglewise.ai/threats/cve-2017-5204-tcpdump-buffer-overflow-in-ipv6-parser  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2017-01-28. Updated: 2026-05-13  
License: CC BY 4.0 with a link back

CVE-2017-5204 · Severity: critical · CVSS 9.8 · Published 2017-01-28

tcpdump is a widely used tool for monitoring and analyzing network traffic. A vulnerability in its IPv6 traffic parser allows an attacker to send specially crafted network packets that can cause the tool to crash or potentially execute unauthorized code. This could disrupt network monitoring operations or allow an attacker to gain a foothold on the system running the analysis tool.

Technologies: [Tcpdump](https://junglewise.ai/threats/technologies/tcpdump). Vendors: [Tcpdump](https://junglewise.ai/threats/vendors/tcpdump).

## Quick answers

**Is CVE-2017-5204 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2017-5204 being exploited in the wild.

**How severe is CVE-2017-5204?** Critical severity, with a CVSS score of 9.8, published 28 January 2017.

**Which products and versions are affected?** Tcpdump before 4.9.0.

**Is there a fix for CVE-2017-5204?** A patch was published on 2017-01-29: Debian Security Advisory DSA-3775-1 issued Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2017-5204 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2017-5204?** Check whether you run Tcpdump at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A buffer overflow vulnerability exists in tcpdump versions prior to 4.9.0 within the IPv6 parsing logic (print-ip6.c:ip6_print()). The flaw is triggered when the application processes specially crafted IPv6 packets. An unauthenticated remote attacker can exploit this by sending malicious packets over a network segment where tcpdump is performing live capture, or by providing a crafted pcap file for offline analysis. Successful exploitation can lead to a denial of service (application crash), an infinite loop, or potentially arbitrary code execution with the privileges of the tcpdump process. The issue was addressed in version 4.9.0.

## Affected products

- tcpdump tcpdump before 4.9.0

## Timeline

- 2017-01-26: advisory: Debian security release announcement for version 4.9.0-1
- 2017-01-28: disclosed: NVD publication date
- 2017-01-29: patched: Debian Security Advisory DSA-3775-1 issued

## References

- [http://www.debian.org/security/2017/dsa-3775](http://www.debian.org/security/2017/dsa-3775)
- [http://www.securityfocus.com/bid/95852](http://www.securityfocus.com/bid/95852)
- [http://www.securitytracker.com/id/1037755](http://www.securitytracker.com/id/1037755)
- [https://access.redhat.com/errata/RHSA-2017:1871](https://access.redhat.com/errata/RHSA-2017:1871)
- [https://security.gentoo.org/glsa/201702-30](https://security.gentoo.org/glsa/201702-30)
- [https://www.mail-archive.com/debian-bugs-dist%40lists.debian.org/msg1494526.html](https://www.mail-archive.com/debian-bugs-dist%40lists.debian.org/msg1494526.html)

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