CVE-2026-0959 is an out-of-bounds write vulnerability classified under CWE-787, found in the IEEE 802.11 protocol dissector component of Wireshark versions 4.4.0 through 4.4.12 and 4.6.0 through 4.6.2. The flaw arises when Wireshark processes specially crafted 802.11 wireless network packets, causing it to write data outside the bounds of allocated memory buffers. This memory corruption leads to a crash of the Wireshark application, resulting in a denial-of-service (DoS) condition. The vulnerability can be triggered remotely by an attacker who can deliver malicious packet captures or inject crafted packets that Wireshark analyzes. Exploitation does not require any privileges or authentication but does require user interaction, such as opening a malicious capture file or live capture containing the crafted packets. The CVSS v3.1 base score is 5.3, reflecting medium severity, with the vector indicating network attack vector (AV:N), high attack complexity (AC:H), no privileges required (PR:N), user interaction required (UI:R), unchanged scope (S:U), no impact on confidentiality or integrity (C:N/I:N), and high impact on availability (A:H). Currently, no public exploits or active exploitation in the wild have been reported. The vulnerability primarily affects the availability of Wireshark, potentially disrupting network analysis and incident response activities. No patches were linked at the time of reporting, so users should monitor vendor advisories for updates.

The primary impact of CVE-2026-0959 is denial of service through application crashes, which can interrupt network traffic analysis and monitoring activities. For European organizations, especially those in sectors such as telecommunications, critical infrastructure, cybersecurity operations, and enterprises relying on Wireshark for network troubleshooting, this could lead to temporary loss of visibility into network traffic and delayed incident response. Although the vulnerability does not allow for code execution or data compromise, the disruption of a key diagnostic tool can indirectly affect security posture and operational continuity. Organizations that use Wireshark in automated or semi-automated network monitoring pipelines may experience outages or require manual intervention to recover. The requirement for user interaction limits the risk somewhat, but targeted attacks via malicious capture files or compromised network segments remain plausible. The absence of known exploits reduces immediate risk but does not preclude future exploitation attempts.

1. Monitor Wireshark Foundation advisories and update Wireshark to patched versions as soon as they become available. 2. Avoid opening untrusted or unauthenticated capture files, especially those received from external or unknown sources. 3. Implement strict network segmentation and filtering to limit exposure to crafted 802.11 packets from untrusted wireless networks. 4. Use sandboxing or isolated environments when analyzing suspicious capture files to contain potential crashes. 5. Educate users and network analysts about the risks of opening unverified capture files and encourage verification of sources. 6. Employ alternative network analysis tools temporarily if Wireshark updates are not yet available. 7. Integrate automated monitoring to detect Wireshark crashes and trigger alerts for rapid response. 8. Review and harden endpoint security policies to prevent unauthorized file downloads or injections that could deliver malicious captures.