CVE-2026-76881 in Wireshark
Summary
by MITRE • 08/20/2026
CMS 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 Common Management Information Protocol (CMIP) dissector found in specific versions of Wireshark, 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 specially crafted CMIP packets during network traffic analysis. The root cause lies in the improper handling of memory allocation and bounds checking within the protocol parsing logic, which fails to validate input data before attempting to access it. When a user opens a capture file containing these maliciously constructed packets or analyzes live traffic that includes such payloads, the dissector encounters an unexpected state that triggers a segmentation fault or similar fatal error, resulting in the immediate termination of the Wireshark process. This represents a classic denial of service scenario where the availability of the security analysis tool is compromised by untrusted input data embedded within network captures.
From a technical perspective, this flaw aligns with CWE-125, Out-of-bounds Read, or potentially CWE-400, Uncontrolled Resource Consumption, depending on the specific memory access pattern that triggers the crash. The dissector relies on parsing complex protocol structures defined by CMIP standards, and when fields are manipulated to exceed expected limits or point to invalid memory addresses, the application lacks sufficient defensive programming practices such as rigorous boundary checks before dereferencing pointers. This type of vulnerability is particularly dangerous in security workflows because analysts frequently handle packet captures from untrusted sources during incident response or threat hunting activities. An attacker who can inject crafted CMIP packets into a network segment being monitored by Wireshark, or distribute malicious capture files via email or file sharing mechanisms, could effectively disrupt the analyst's ability to perform critical forensic investigations and real-time monitoring tasks.
The operational impact of this vulnerability extends beyond simple application instability. In professional security environments, Wireshark is often used as a primary tool for deep packet inspection and protocol analysis. A crash in such a tool can lead to significant downtime during active incident response efforts, potentially delaying the identification and mitigation of other ongoing threats. Furthermore, if an analyst relies on automated scripts or plugins that utilize the Wireshark engine programmatically, this vulnerability could disrupt broader automation pipelines designed for network monitoring and anomaly detection. The lack of robust error handling means that even a single malformed packet can halt the entire session, forcing the user to restart the application and potentially lose unsaved work or context related to their investigation. This underscores the importance of input validation in tools that process arbitrary data streams from external sources.
To mitigate this risk, users operating within the affected version ranges must upgrade immediately to a patched release where these memory handling issues have been resolved by the development team. Until an update is applied, analysts should exercise extreme caution when opening capture files obtained from untrusted origins or analyzing live traffic that includes CMIP protocol elements unless they are running in a isolated virtual machine environment with limited privileges. It is also advisable to disable the CMIP dissector if it is not required for specific network monitoring tasks, thereby reducing the attack surface presented by this component. Organizations should implement strict version control policies for their security tooling and ensure that patch management processes include rapid deployment of updates for critical vulnerabilities in analysis software. Regularly updating Wireshark ensures access to these essential stability fixes and maintains the integrity of forensic workflows against potential denial-of-service attacks targeting data processing components.