# CVE-2016-7940: tcpdump buffer overflow in STP parser

Source: https://junglewise.ai/threats/cve-2016-7940-tcpdump-buffer-overflow-in-stp-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-2016-7940 · Severity: critical · CVSS 9.8 · Published 2017-01-28

tcpdump is a widely used command-line tool for monitoring and analyzing network traffic. A vulnerability in its Spanning Tree Protocol (STP) parser allows an attacker to send specially crafted network packets that can cause the application to crash or potentially execute unauthorized code. This could lead to a disruption of network monitoring services or provide a foothold for further attacks on the system running the tool.

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

## Quick answers

**Is CVE-2016-7940 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2016-7940 being exploited in the wild.

**How severe is CVE-2016-7940?** Critical severity, with a CVSS score of 9.8, published 28 January 2017.

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

**Is there a fix for CVE-2016-7940?** A patch was published on 2017-01-29: Debian released fixed version 4.9.0-1 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2016-7940 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2016-7940?** Check whether you run Tcpdump. 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 the Spanning Tree Protocol (STP) parser of tcpdump versions prior to 4.9.0. The flaw is located within multiple functions in the 'print-stp.c' source file. A remote attacker can exploit this by sending specially crafted STP packets to a network segment where tcpdump is performing live capture, or by tricking a user into opening a malicious pcap file. Successful exploitation can lead to a denial of service (application crash) or 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

- 2017-01-27: advisory: NVD publication date
- 2017-01-29: patched: Debian released fixed version 4.9.0-1

## 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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