CVE-2026-96423 Wireshark Foundation CVE debrief

Who should care

Network administrators and security teams who use Wireshark for network protocol analysis should be aware of this vulnerability and take steps to update Wireshark to a version that is not vulnerable.

Why it matters

A heap-based buffer overflow vulnerability in Wireshark's X11 protocol dissector can be exploited to cause a denial of service. Network administrators and security teams using Wireshark should update to a secure version and monitor for patches.

• Denial of service (DoS) due to application crash
• Potential for exploitation by attackers to disrupt network analysis
• Need for updating Wireshark to a secure version
• Importance of monitoring Wireshark for updates and patches

Technical summary

The X11 protocol dissector in Wireshark is vulnerable to a heap-based buffer overflow. This vulnerability affects Wireshark versions 4.6.0 to 4.6.8 and 4.4.0 to 4.4.18. An attacker could exploit this vulnerability to cause a denial of service (DoS) by crashing the Wireshark application. The vulnerability has a CVSS score of 5.5 and a medium severity. The affected versions of Wireshark are 4.6.0 to 4.6.8 and 4.4.0 to 4.4.18. The vulnerability can be exploited to cause a denial of service. Network administrators and security teams using Wireshark should update to a secure version and monitor for patches.

Defensive priority

Medium priority should be given to updating Wireshark to a version that is not vulnerable, as the vulnerability can be exploited to cause a denial of service.

Recommended defensive actions

• Update Wireshark to a version that is not vulnerable
• Monitor Wireshark for updates and patches
• Consider implementing network traffic monitoring to detect potential exploitation attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is caused by a heap-based buffer overflow in the X11 protocol dissector. The affected versions of Wireshark are 4.6.0 to 4.6.8 and 4.4.0 to 4.4.18. The vulnerability can be exploited to cause a denial of service.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.