CVE-2026-7378: Sharkd Denial of Service Vulnerability

CVE-2026-7378 Overview

CVE-2026-7378 is a heap-based buffer overflow vulnerability in sharkd, the Wireshark daemon, affecting versions 4.6.0 to 4.6.4 and 4.4.0 to 4.4.14. This vulnerability allows an attacker to cause a denial of service condition by triggering a crash in the sharkd process. The vulnerability is classified as CWE-122 (Heap-based Buffer Overflow), which occurs when a program writes data outside the bounds of allocated heap memory.

Critical Impact
Successful exploitation of this vulnerability results in denial of service through crashing the sharkd daemon, potentially disrupting network analysis and monitoring operations.

Affected Products

Wireshark sharkd versions 4.6.0 to 4.6.4
Wireshark sharkd versions 4.4.0 to 4.4.14

Discovery Timeline

2026-04-30 - CVE CVE-2026-7378 published to NVD
2026-04-30 - Last updated in NVD database

Technical Details for CVE-2026-7378

Vulnerability Analysis

This vulnerability is a heap-based buffer overflow (CWE-122) in sharkd, the daemon mode of Wireshark used for programmatic access to packet analysis capabilities. The flaw allows an attacker with local access to craft malicious input that triggers a heap buffer overflow, causing the sharkd process to crash. While the vulnerability requires user interaction and local access, it can result in complete disruption of packet capture and analysis services running under sharkd.

The vulnerability affects the availability of the system without impacting confidentiality or integrity. This makes it particularly concerning for environments relying on continuous network monitoring, as a crash in sharkd could create blind spots in security visibility.

Root Cause

The root cause of this vulnerability is improper boundary checking when handling heap-allocated memory buffers in sharkd. When processing certain inputs, the application fails to properly validate the size of data being written to heap memory, resulting in writes beyond the allocated buffer boundaries. This heap-based buffer overflow (CWE-122) ultimately leads to memory corruption and application crash.

Attack Vector

The attack requires local access to the target system and user interaction to exploit. An attacker would need to provide specially crafted input to the sharkd daemon that triggers the heap overflow condition. The local attack vector means the attacker must have some level of access to the system running sharkd, such as the ability to submit capture files or interact with the daemon's API.

The vulnerability manifests when sharkd processes malicious input that overflows heap-allocated buffers. For technical details on the specific crash conditions, refer to the GitLab Wireshark Work Item and the Wireshark Security Advisory WNPA-SEC-2026-49.

Detection Methods for CVE-2026-7378

Indicators of Compromise

Unexpected sharkd process crashes or service restarts
Core dump files generated by sharkd with heap corruption signatures
Unusual or malformed capture files being processed by sharkd
System logs indicating sharkd segmentation faults or memory access violations

Detection Strategies

Monitor system logs for sharkd crash events and segmentation faults
Implement process monitoring to detect unexpected sharkd terminations
Use endpoint detection to identify attempts to interact with sharkd using crafted inputs
Deploy file integrity monitoring on capture file directories

Monitoring Recommendations

Configure alerting for sharkd service availability and unexpected restarts
Monitor heap memory usage patterns of sharkd processes for anomalies
Review access logs for the sharkd daemon API endpoints
Implement application crash monitoring with automated incident creation

How to Mitigate CVE-2026-7378

Immediate Actions Required

Upgrade sharkd to a patched version beyond 4.6.4 (for 4.6.x branch) or beyond 4.4.14 (for 4.4.x branch)
Restrict local access to systems running sharkd to authorized personnel only
Implement input validation for capture files processed by sharkd
Consider disabling sharkd if not actively required for operations

Patch Information

Wireshark has released security updates addressing this vulnerability. Users should upgrade to the latest stable versions that contain the fix. For detailed patch information and download links, refer to the Wireshark Security Advisory WNPA-SEC-2026-49.

Workarounds

Restrict access to sharkd to trusted users and systems only
Implement network segmentation to limit exposure of systems running sharkd
Use process supervision to automatically restart sharkd if it crashes
Validate capture files from untrusted sources before processing with sharkd

bash

# Configuration example
# Restrict sharkd access to localhost only
# Add to sharkd startup configuration or wrapper script
sharkd -a tcp:127.0.0.1:4446

# Set up process monitoring with systemd
# Create /etc/systemd/system/sharkd.service with restart policy
[Service]
Restart=always
RestartSec=5