Wireshark Vulnerability Allows Attackers to Launch DoS Attacks

A critical security vulnerability, tracked as CVE-2025-5601, was disclosed on June 4, 2025, affecting Wireshark versions 4.4.0 to 4.4.6 and 4.2.0 to 4.2.12.

This flaw, identified as “Dissection engine crash” (wnpa-sec-2025-02), stems from a bug in the column utility module used by Wireshark’s dissectors.

The vulnerability allows attackers to cause a denial of service (DoS) by injecting malformed packets onto a network or by convincing a user to open a specially crafted capture file.

The technical root of the issue lies in how Wireshark handles column data during packet dissection.

Specifically, a buffer copy operation occurs without proper input size checking, leading to potential memory corruption and application crashes.

The bug can be triggered either during live packet capture or when analyzing saved packet trace files, making it a versatile attack vector.

Exploitation Scenarios and Technical Impact

The vulnerability is classified as high severity, with a CVSS score of 7.8.

No active exploits have been reported in the wild, but the risk remains significant due to the ease of triggering the crash. Attackers can exploit the flaw in two primary ways:

• Packet Injection: Malicious actors inject malformed packets into a network monitored by Wireshark, causing the application to crash when it attempts to dissect the packet.
• Crafted Capture Files: Attackers distribute specially crafted .pcap or .pcapng files. When a user opens such a file in an affected version of Wireshark, the application crashes immediately.

A related bug report highlights that even clicking on a column header in the packet list can cause a segmentation fault (SEGV) in affected versions, further amplifying the risk.

This behavior is consistent across different trace files and columns, indicating a fundamental flaw in the column handling logic.

Example Code Reference

The vulnerability is associated with unsafe buffer operations in the column utility module.

While the exact code snippet is proprietary, the following pseudocode illustrates the unsafe operation:

c// Vulnerable buffer copy operation
void copy_column_data(char *dest, const char *src, size_t dest_size) {
    // Missing bounds check
    strcpy(dest, src); // Potential buffer overflow if src > dest_size
}

A secure implementation should use strncpy or similar functions with explicit bounds checking to prevent buffer overflows.

Affected Versions, Patch Status, and Mitigation

The table below summarizes the affected and fixed versions:

Users are strongly advised to upgrade to Wireshark 4.4.7, 4.2.13, or later to mitigate this vulnerability.

The patch addresses the buffer handling flaw in the column utility module, preventing crashes from malformed input.

For environments where immediate upgrades are not feasible, users should avoid opening untrusted packet capture files and restrict network access to trusted sources only.

The rapid disclosure and patching of this vulnerability underscore the importance of timely updates and proactive security practices in network analysis environments.

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