Mitigation Strategies

The immediate and recommended mitigation step is to upgrade Wireshark to versions 4.6.5 or 4.4.15 or later, where this vulnerability has been fixed.

Until the upgrade is applied, avoid opening untrusted or suspicious packet trace files that may contain maliciously crafted MBIM packets.

Additionally, limit exposure to untrusted MBIM traffic or disable MBIM protocol dissector in Wireshark if possible to reduce the risk of triggering the infinite loop.

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Executive Summary

The CVE-2026-6519 vulnerability is an infinite loop issue in Wireshark's MBIM protocol dissector. It occurs because the dissector reads a buffer length value from the MBIM message header without validating it against the actual packet size. A maliciously crafted large value can cause the dissector to enter an infinite loop while parsing the packet, leading to excessive processing.

Specifically, the function mbim_dissect_tlv_ie_list() in packet-mbim.c uses an unchecked buffer_length parameter, causing the loop condition to never terminate when given a large manipulated value. This results in Wireshark consuming excessive CPU resources or crashing.

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Impact Analysis

This vulnerability can cause a denial-of-service (DoS) condition by making Wireshark enter an infinite loop and consume excessive CPU resources. This can lead to application crashes or system slowdowns when processing maliciously crafted MBIM packets or packet trace files.

An attacker could exploit this by sending specially crafted MBIM traffic or tricking a user into opening a malicious packet capture file, potentially disrupting network analysis or forensic activities.

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Detection Guidance

This vulnerability can be detected by analyzing MBIM protocol traffic for malformed packets that contain an abnormally large buffer length value in the MBIM COMMAND_MSG header. Specifically, the `info_buff_len` field is read without validation and can be manipulated to a large value (e.g., 536MB) to trigger the infinite loop.

A practical approach is to capture MBIM traffic and inspect the `info_buff_len` field in the packets. Using Wireshark itself to open suspicious PCAP files may trigger the issue if the vulnerability is present.

A proof-of-concept PCAP file named `poc_mbim.pcapng` demonstrates the vulnerability by containing a fragmented MBIM message with a manipulated `info_buff_len`.

While no specific commands are provided in the resources, network administrators can use packet capture tools like tcpdump or tshark to capture MBIM traffic and then analyze the `info_buff_len` field in the MBIM COMMAND_MSG header for unusually large values.

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Compliance Impact

The provided information does not specify any direct impact of the CVE-2026-6519 vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

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