CVE-2026-6521 Loop with Unreachable Exit Condition ('Infinite Loop') in Wireshark
An attacker can cause a denial of service in Wireshark by sending crafted OpenFlow v5 packets that trigger an infinite loop in the dissector.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-6521?
CVE-2026-6521 is a medium-severity denial of service vulnerability in Wireshark Wireshark, published on 30 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
OpenFlow v5 protocol dissector infinite loops in Wireshark 4.6.0 to 4.6.4 and 4.4.0 to 4.4.14 allows denial of service
Weakness: CWE-835
Which versions are affected by CVE-2026-6521?
It affects 1 product.
Products include Wireshark Wireshark.
How do I fix CVE-2026-6521?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-6521 being exploited?
There is no known exploitation of CVE-2026-6521 in the wild and no public exploit code.
Other vulnerabilities in Wireshark Wireshark
Sources
Also known as AZL-85208, DEBIAN-CVE-2026-6521, GHSA-9m6f-gr3v-5w4w, UBUNTU-CVE-2026-6521.