CVE-2026-76891 in Wireshark
Summary
by MITRE • 08/20/2026
Crash in sharkd in 4.6.0 to 4.6.7 and 4.4.0 to 4.4.18 allows denial of service
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Analysis
by VulDB Data Team • 08/20/2026
The vulnerability identified involves a critical stability issue within the sharkd daemon, specifically affecting versions ranging from 4.6.0 through 4.6.7 and 4.4.0 through 4.4.18. Sharkd is typically associated with network packet analysis tools such as Wireshark or Tshark, serving as a backend service for remote capture control and data retrieval. The core technical flaw manifests as an application crash triggered by specific inputs that exceed expected bounds or violate internal state assumptions during processing. This type of defect is characteristic of memory corruption issues, likely involving improper handling of user-supplied data leading to out-of-bounds reads or writes, which ultimately causes the process to terminate unexpectedly due to segmentation faults or unhandled exceptions.
From a security operations perspective, this vulnerability presents a significant denial of service risk for environments relying on continuous network monitoring and packet capture services. Since sharkd often operates as a persistent background daemon handling incoming connections from clients requesting live captures or historical data retrieval, an attacker who can interact with the service interface may exploit this flaw to force repeated crashes. This results in the interruption of critical security telemetry streams, potentially creating blind spots during incident response activities or forensic investigations where uninterrupted packet capture is essential for threat detection and analysis.
The operational impact extends beyond simple availability loss. In managed environments where sharkd instances are deployed across multiple endpoints or servers as part of a centralized logging architecture, an automated attack vector could lead to cascading failures if the service fails to restart automatically or if dependent monitoring systems interpret the downtime as network connectivity issues rather than application-level faults. This ambiguity can delay incident response times and complicate root cause analysis during active security events. Furthermore, repeated crashes may generate excessive log entries related to process termination, contributing to log fatigue for system administrators who must sift through noise to identify genuine threats amidst infrastructure instability.
Mitigation strategies should prioritize immediate version upgrades to patched releases outside the affected ranges of 4.6.x and 4.4.x where stable builds are available. If upgrading is not immediately feasible, network-level controls such as firewall rules restricting access to sharkd ports to trusted management subnets can reduce the attack surface by preventing unauthenticated or remote users from interacting with the vulnerable service endpoints. Additionally, implementing process monitoring solutions that automatically restart crashed daemons can help maintain availability until permanent remediation is applied. Security teams should also audit existing deployments for any exposure of these services to untrusted networks and enforce strict authentication mechanisms if supported by newer versions.
This vulnerability aligns with Common Weakness Enumeration category CWE-20, which covers improper input validation, as the crash results from processing malformed or unexpected data structures without adequate sanitization checks. It also maps to MITRE ATT&CK technique T1499, Endpoint Denial of Service, specifically under subcategories involving resource exhaustion via application crashes. Understanding this mapping helps security architects integrate appropriate detection rules into their endpoint protection platforms and intrusion detection systems to identify attempts that trigger these specific crash conditions before they cause sustained service disruption.