CVE-2025-13945 is a vulnerability identified in Wireshark version 4.6.0, specifically within its HTTP3 protocol dissector component. The root cause is an improperly controlled sequential memory allocation, categorized under CWE-1325, which leads to a crash when processing malformed or malicious HTTP3 packets. This crash results in a denial of service (DoS) condition by terminating the Wireshark process unexpectedly. The vulnerability's CVSS 3.1 base score is 5.5, indicating medium severity. The attack vector is local (AV:L), meaning the attacker must have local network access or system access to trigger the flaw. No privileges are required (PR:N), but user interaction (UI:R) is necessary, implying that the user must initiate some action, such as opening a crafted capture file or analyzing malicious traffic. The scope remains unchanged (S:U), and the impact is limited to availability (A:H), with no confidentiality or integrity impact. No public exploits have been reported yet, and no patches are currently linked, suggesting the vulnerability is newly disclosed. Wireshark, widely used for network protocol analysis, is critical for network troubleshooting and security monitoring, so a DoS in this tool can disrupt these activities. The vulnerability highlights the risks of parsing complex, evolving protocols like HTTP3 without robust memory management.

For European organizations, this vulnerability primarily threatens the availability of Wireshark during network analysis tasks. Organizations relying on Wireshark 4.6.0 for real-time traffic inspection, incident response, or forensic analysis may experience interruptions if an attacker crafts malicious HTTP3 traffic or files that trigger the crash. This could delay detection and response to network incidents, potentially increasing exposure to other threats. Although exploitation requires local access and user interaction, insider threats or compromised internal systems could leverage this flaw to disrupt security operations. The lack of confidentiality or integrity impact limits the risk to data breaches or manipulation. However, the disruption of a key network analysis tool could indirectly affect operational security and incident management. European critical infrastructure sectors, financial institutions, and large enterprises with active network monitoring are particularly sensitive to such availability disruptions.

Since no official patch is currently available, European organizations should implement the following mitigations: 1) Avoid using Wireshark version 4.6.0 for analyzing HTTP3 traffic until a patch is released; downgrade to a previous stable version without this vulnerability if feasible. 2) Restrict local access to systems running Wireshark to trusted personnel only, minimizing exposure to malicious actors. 3) Educate users to avoid opening untrusted capture files or analyzing suspicious HTTP3 traffic without proper safeguards. 4) Monitor network traffic for anomalous or malformed HTTP3 packets that could be used to trigger the vulnerability. 5) Once a patch is released, prioritize updating Wireshark installations promptly. 6) Consider deploying alternative network analysis tools temporarily if Wireshark usage is critical and patching is delayed. 7) Implement endpoint protection and network segmentation to limit the ability of attackers to deliver malicious payloads locally.