CVE-2026-76883 Overview
CVE-2026-76883 is a denial-of-service vulnerability in the Wireshark Catapult DCT2000 file parser. Affected versions include Wireshark 4.6.0 through 4.6.7 and 4.4.0 through 4.4.18. The flaw is classified as a heap-based buffer overflow [CWE-122] triggered when the parser processes a crafted DCT2000 capture file. Successful exploitation crashes the Wireshark process, disrupting packet analysis workflows. The vulnerability requires local file access and user interaction, such as opening a malicious capture file or receiving one through a live capture feed.
Critical Impact
A crafted Catapult DCT2000 capture file causes a heap buffer overflow that crashes Wireshark, producing a denial-of-service condition for analysts relying on the tool.
Affected Products
- Wireshark 4.6.0 through 4.6.7
- Wireshark 4.4.0 through 4.4.18
- Catapult DCT2000 file parser component
Discovery Timeline
- 2026-08-19 - CVE-2026-76883 published to NVD
- 2026-08-20 - Last updated in NVD database
Technical Details for CVE-2026-76883
Vulnerability Analysis
The vulnerability resides in the Catapult DCT2000 file parser distributed with Wireshark. Parsing a malformed DCT2000 capture file triggers a heap-based buffer overflow, resulting in a process crash. The issue is limited to availability impact and does not compromise confidentiality or integrity of the host system. Exploitation requires the target user to open the malicious file locally or process it through a capture workflow. Because Wireshark is commonly used during incident response and network forensics, repeated crashes can disrupt investigations.
Root Cause
The root cause is improper bounds checking within the DCT2000 dissector when reading fields from a capture file. The parser writes beyond an allocated heap region while processing attacker-controlled data, corrupting adjacent memory and triggering an abort. See the Wireshark Security Advisory WNPA-SEC-2026-74 and GitLab Work Item #21427 for technical details.
Attack Vector
An attacker crafts a malicious DCT2000 capture file and delivers it to a target analyst through email, shared storage, or a threat-intelligence feed. When the analyst opens the file in a vulnerable Wireshark build, the DCT2000 dissector processes the malformed structure and the process crashes. The attack requires user interaction and local file access, and does not yield code execution based on the current advisory scope.
The vulnerability manifests during structured parsing of DCT2000 trace records. See the vendor advisory for annotated source references and the corrective patch.
Detection Methods for CVE-2026-76883
Indicators of Compromise
- Unexpected Wireshark or tshark process crashes correlated with opening or importing .out DCT2000 capture files.
- Application error logs referencing heap corruption in the catapult_dct2000 dissector module.
- Delivery of DCT2000-format capture files from untrusted external sources to analyst workstations.
Detection Strategies
- Inventory endpoints for installed Wireshark versions and flag hosts running 4.6.0–4.6.7 or 4.4.0–4.4.18.
- Monitor process telemetry for repeated abnormal termination of wireshark.exe, wireshark, or tshark binaries.
- Inspect email and file-transfer gateways for DCT2000 capture files originating outside trusted forensic pipelines.
Monitoring Recommendations
- Forward Wireshark crash events and Windows Error Reporting or Linux coredump entries to a centralized log platform.
- Alert on repeated Wireshark process termination on the same host within a short time window.
- Track file-open telemetry for DCT2000 extensions on analyst systems to identify targeting patterns.
How to Mitigate CVE-2026-76883
Immediate Actions Required
- Upgrade Wireshark to a fixed release above the 4.6.7 and 4.4.18 boundaries as published by the Wireshark Foundation.
- Restrict opening of DCT2000 capture files to trusted sources until all analyst workstations are patched.
- Communicate the advisory to incident response and network forensics teams that regularly handle third-party capture files.
Patch Information
The Wireshark Foundation addressed the issue in the DCT2000 dissector. Refer to Wireshark Security Advisory WNPA-SEC-2026-74 for the corrected version list and to GitLab Work Item #21427 for the source-level fix. Apply the vendor-supplied installer or use the operating system package manager to update.
Workarounds
- Disable the Catapult DCT2000 dissector in Analyze > Enabled Protocols if patching is not immediately possible.
- Use tshark with the --disable-protocol dct2000 flag when processing capture files from untrusted sources.
- Open unknown capture files in an isolated virtual machine to contain crash impact on production analyst workstations.
# Configuration example
tshark --disable-protocol dct2000 -r suspicious_capture.out
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
