CVE-2026-76924 in Wireshark
Summary
by MITRE • 08/20/2026
Kerberos protocol dissector crash 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 flaw within the Kerberos protocol dissector found in specific versions of network analysis software, specifically ranging from version 4.6.0 through 4.6.7 and from 4.4.0 through 4.4.18. This issue manifests as an application crash when processing malformed or unexpectedly structured Kerberos packets during traffic capture or file import operations. The root cause of this instability lies in the improper handling of memory allocation and bounds checking within the parser logic responsible for dissecting Kerberos authentication messages. When a crafted packet containing invalid data structures, such as incorrect length fields or unexpected tag values, is processed by the dissector, it triggers an out-of-bounds read or write operation that leads to immediate termination of the application process. This type of memory corruption error represents a significant reliability risk for security professionals and network administrators who rely on these tools for continuous monitoring and forensic analysis without interruption.
From a technical perspective, this flaw aligns with Common Weakness Enumeration category CWE-125, which describes Out-of-bounds Read vulnerabilities where software reads data past the end or before the beginning of the intended buffer. In the context of protocol dissectors, such errors often occur when the parser fails to validate the integrity of packet headers against declared lengths before attempting to extract payload data. The lack of rigorous input validation allows an attacker who can inject malicious traffic into a monitored network segment to exploit this weakness remotely. By sending specially crafted Kerberos packets that trigger the memory access violation, an adversary can cause the dissector application to crash repeatedly or permanently, thereby disrupting the ability of security teams to monitor authentication events and detect other potential threats within the environment.
The operational impact of this vulnerability is primarily centered on denial of service against critical monitoring infrastructure. Network security tools are often deployed as always-on services that ingest high volumes of traffic in real-time. A crash in the Kerberos dissector not only halts the analysis of authentication flows but may also destabilize the entire application if error handling mechanisms fail to isolate the fault within a single protocol parser thread or module. This disruption creates blind spots during active investigations, potentially allowing malicious actors to conduct unauthorized access attempts or lateral movement without detection. Furthermore, in environments where automated alerting systems depend on continuous data ingestion from these tools, the loss of visibility can delay incident response times and compromise overall security posture. The vulnerability affects both live capture scenarios and post-mortem analysis of saved packet files, meaning that even archived traffic containing malicious Kerberos packets could trigger the crash upon review.
Mitigation strategies for this issue involve immediate software updates to patched versions released by the vendor after version 4.6.7 and 4.4.18. Organizations should verify their current deployment status against these version ranges and apply the latest stable release which includes corrected input validation logic and robust error handling within the Kerberos parser. In cases where updating is not immediately feasible, temporary mitigations may include configuring network access control lists to restrict exposure of monitoring endpoints to trusted sources only or disabling specific protocol dissectors if they are not essential for current operational requirements. Additionally, implementing strict packet filtering rules at the network perimeter can help prevent malformed traffic from reaching the analysis tools. Long-term resilience requires integrating fuzzing techniques into development pipelines to detect similar parsing errors before deployment and adhering to secure coding practices that emphasize defensive programming against buffer overflows and invalid state transitions in protocol parsers. This vulnerability is categorized under ATT&CK technique T1498, Network Denial of Service, as it enables an attacker to disrupt the availability of security monitoring capabilities through resource exhaustion or application failure induced by malicious input.