CVE-2025-13946: 
Wireshark vulnerability analysis and mitigation

CVE-2025-13946 is an infinite loop vulnerability in the MEGACO dissector of Wireshark that allows a local attacker to cause a denial of service by supplying a malformed network packet or capture file. It affects Wireshark versions 4.6.0 through 4.6.1 and 4.4.0 through 4.4.11. The vulnerability was published on December 3, 2025, with patches released shortly after. It carries a CVSS v3.1 base score of 5.5 (Medium) (Wireshark Advisory, Feedly).

The root cause is classified as CWE-835 (Loop with Unreachable Exit Condition / Infinite Loop), occurring within Wireshark's MEGACO protocol dissector. When processing a specially crafted malformed network packet or capture file, the dissector enters an infinite loop with no reachable exit condition, causing the application to hang indefinitely. Exploitation requires user interaction — specifically, the victim must open a malicious capture file or receive a crafted packet while capturing traffic — and no elevated privileges are needed (Wireshark Advisory, GitLab Issue).

Successful exploitation causes Wireshark to become completely unresponsive, effectively denying the analyst the ability to perform network analysis until the application is manually terminated and restarted. There is no impact on confidentiality or integrity — the vulnerability is limited to availability (high). Because Wireshark is a passive analysis tool, exploitation does not enable lateral movement or data exfiltration, but it could disrupt incident response or forensic workflows that depend on the tool (Feedly, Wireshark Advisory).

A proof-of-concept reference exists in the form of the GitLab issue report that triggered the fix, but there is no evidence of active in-the-wild exploitation or weaponized exploit kits (GitLab Issue). The EPSS score is extremely low at approximately 0.013%, reflecting minimal likelihood of near-term exploitation. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. No threat actor attribution has been reported (Feedly).

1. Craft a malformed MEGACO packet or capture file: Create a network capture file (e.g., .pcap or .pcapng) containing a malformed MEGACO protocol message designed to trigger the infinite loop condition in the dissector.
2. Deliver the file to the target: Send the crafted capture file to the victim via email, file share, or other means, or position the malformed packet on a network segment where the victim is actively capturing traffic with Wireshark.
3. Trigger dissection: The victim opens the malicious capture file in an affected version of Wireshark (4.4.0–4.4.11 or 4.6.0–4.6.1), or the malformed packet is captured live during a session.
4. Denial of service achieved: The MEGACO dissector enters an infinite loop, causing Wireshark to hang and consume CPU resources until the process is manually killed, disrupting any ongoing network analysis (GitLab Issue, Wireshark Advisory).

• Process: Wireshark process (wireshark, tshark, or dumpcap) consuming 100% CPU for an extended period with no user-visible progress.
• File System: Presence of unexpected or externally sourced .pcap/.pcapng files containing MEGACO protocol traffic in user download or temp directories.
• Logs: Application crash or hang logs generated by the OS (e.g., Windows Event Log application errors or Linux dmesg/journal entries) referencing the Wireshark process becoming unresponsive.

Users should upgrade Wireshark to version 4.4.12 or 4.6.2, which contain the fix for this vulnerability (Wireshark Advisory). As a workaround prior to patching, users should avoid opening capture files from untrusted or unknown sources, and restrict access to Wireshark to authorized personnel only. Debian and other Linux distributions have also issued updated packages addressing this CVE (Debian LTS).

Coverage has been primarily technical and low-key, consistent with the medium severity rating. Security news outlets such as CyberSecurityNews covered the Wireshark 4.6.2 release that addressed this and related vulnerabilities (CyberSecurityNews). Linux distribution communities (Solus, Debian, SUSE, Amazon Linux) issued their own advisories and package updates. No significant controversy or notable researcher commentary beyond standard patch reporting has been observed.