CVE-2026-76887: Wireshark Dissection Engine DoS Flaw

CVE-2026-76887 Overview

CVE-2026-76887 is a denial-of-service vulnerability in the Wireshark network protocol analyzer. The flaw resides in the dissection engine and affects Wireshark versions 4.6.0 through 4.6.7 and 4.4.0 through 4.4.18. A crafted packet or capture file processed by a vulnerable dissector triggers a crash, terminating the Wireshark process. The issue is classified under [CWE-122] as a heap-based buffer overflow condition. Exploitation requires user interaction, such as opening a malicious capture file or dissecting live traffic on a monitored interface. No arbitrary code execution or data disclosure has been reported; impact is limited to availability of the analyzer process.

Critical Impact
A crafted packet or capture file crashes the Wireshark dissection engine, disrupting network analysis workflows and forensic investigations.

Affected Products

Wireshark 4.6.0 through 4.6.7
Wireshark 4.4.0 through 4.4.18
Downstream distributions bundling the affected Wireshark releases

Discovery Timeline

2026-08-19 - CVE-2026-76887 published to NVD
2026-08-20 - Last updated in NVD database

Technical Details for CVE-2026-76887

Vulnerability Analysis

The vulnerability affects the Wireshark dissection engine, the component responsible for parsing captured network traffic into protocol-specific fields. When the engine processes a malformed packet, a heap-based buffer overflow condition ([CWE-122]) leads to a process crash. The result is denial of service for the analyst using Wireshark, TShark, or related command-line tools that share the dissector libraries.

Exploitation does not grant code execution or expose captured data. However, in environments where Wireshark is used for continuous monitoring or automated pcap processing pipelines, repeated crashes disrupt analysis workflows and may cause loss of visibility into live traffic.

Root Cause

The root cause is improper bounds handling within a specific dissector in the affected Wireshark releases. When the dissector encounters unexpected field values or lengths, it writes or reads beyond an allocated heap buffer, causing memory corruption that immediately terminates the process. Technical specifics of the affected dissector are documented in the Wireshark Security Advisory and the corresponding GitLab Wireshark Work Item.

Attack Vector

An attacker delivers a crafted packet on a network segment where Wireshark performs live capture, or provides a malicious capture file for an analyst to open. User interaction is required to trigger the crash in file-based scenarios. Network-based exploitation requires the target host to actively dissect the malicious traffic.

No public proof-of-concept exploit is available. Refer to the Wireshark Security Advisory for dissector-level details.

Detection Methods for CVE-2026-76887

Indicators of Compromise

Unexpected termination of wireshark, tshark, dumpcap, or rawshark processes on analyst workstations
Core dump files or crash reports generated by the Wireshark process after opening a specific pcap file
Repeated dissector crashes correlating with a specific source IP or capture source

Detection Strategies

Inventory installed Wireshark versions across analyst workstations and forensic hosts, flagging any within the 4.6.0–4.6.7 or 4.4.0–4.4.18 ranges
Monitor endpoint telemetry for abnormal exits of Wireshark-family processes accompanied by capture file access events
Correlate crash events with recently opened pcap files or active capture interfaces to identify suspect traffic sources

Monitoring Recommendations

Enable operating system crash reporting on hosts running Wireshark to preserve forensic artifacts
Alert on process termination events for Wireshark binaries in security operations tooling
Track pcap files received from untrusted sources and quarantine them for analysis in isolated environments

How to Mitigate CVE-2026-76887

Immediate Actions Required

Upgrade Wireshark to a fixed release published by the Wireshark Foundation as noted in the Wireshark Security Advisory
Avoid opening untrusted pcap or pcapng files on vulnerable Wireshark installations
Restrict live capture on production-critical monitoring hosts until patched builds are deployed

Patch Information

The Wireshark Foundation addresses the crash in releases following 4.6.7 and 4.4.18. Consult the Wireshark Security Advisory and the GitLab Wireshark Work Item for the specific commit and release version containing the fix. Package maintainers for Linux distributions typically backport the patch; verify updates through the distribution's security channel.

Workarounds

Disable the affected dissector in Wireshark preferences under Analyze > Enabled Protocols if operational needs prevent immediate upgrade
Process untrusted pcap files inside an isolated virtual machine or sandbox to contain crash impact
Use a non-vulnerable Wireshark version on a separate host for analysis of externally sourced captures

bash

# Verify installed Wireshark version on Linux
wireshark --version | head -n 1
tshark --version | head -n 1

# Example: disable a specific dissector at launch
tshark -o "<protocol>.enabled:FALSE" -r suspect.pcap