CVE-2026-0961 is an out-of-bounds write vulnerability classified under CWE-787 found in the BLF (Binary Logging Format) file parser component of Wireshark versions 4.4.0 through 4.4.12 and 4.6.0 through 4.6.2. The vulnerability arises when Wireshark processes a specially crafted BLF file, which causes the parser to write data outside the bounds of allocated memory. This memory corruption leads to a crash of the Wireshark application, resulting in a denial of service (DoS) condition. The attack vector requires local access since the user must open a malicious BLF file, implying user interaction is necessary. The CVSS v3.1 score is 5.5 (medium), reflecting the low attack complexity and no privileges required, but the need for user interaction and local access limits exploitation scope. No known exploits have been reported in the wild, and no official patches have been published at the time of this report. The vulnerability impacts availability but does not compromise confidentiality or integrity of data. Wireshark is widely used for network protocol analysis and forensic investigations, making stability critical for security teams and network administrators. The flaw could be leveraged by attackers to disrupt analysis workflows or crash monitoring tools, potentially delaying incident response or network troubleshooting.

For European organizations, the primary impact of CVE-2026-0961 is the disruption of network monitoring and forensic analysis capabilities due to Wireshark crashes. This can hinder timely detection and response to network incidents, affecting operational continuity especially in sectors reliant on real-time network visibility such as telecommunications, finance, and critical infrastructure. Although the vulnerability does not lead to data breaches or privilege escalation, denial of service in security tools can indirectly increase risk exposure by delaying threat detection. Organizations using affected Wireshark versions on analyst workstations or automated analysis systems may experience reduced productivity and increased operational risk. The absence of known exploits reduces immediate threat but does not eliminate the risk of targeted attacks exploiting this flaw. European entities with stringent compliance requirements for network security monitoring should prioritize addressing this vulnerability to maintain regulatory adherence and service reliability.

To mitigate CVE-2026-0961, organizations should: 1) Avoid opening BLF files from untrusted or unknown sources to prevent triggering the out-of-bounds write. 2) Monitor official Wireshark Foundation channels for patches or updates addressing this vulnerability and apply them promptly once available. 3) Implement endpoint protection measures that can detect and block attempts to open malicious files or anomalous application crashes. 4) Use sandboxing or isolated environments for analyzing suspicious BLF files to contain potential crashes. 5) Educate users and analysts about the risks of opening unverified BLF files and enforce strict file handling policies. 6) Consider deploying alternative network analysis tools temporarily if Wireshark stability is critical and patches are delayed. 7) Maintain robust incident response plans to quickly recover from potential DoS conditions affecting security monitoring tools. These steps go beyond generic advice by focusing on file source validation, user awareness, and operational continuity.