CVE-2026-96423
MEDIUMCVE-2026-96423 is a medium-severity (CVSS 5.5) CWE-122 vulnerability. No vendor fix is recorded yet; mitigation options are listed below.
X11 protocol dissector crash in 4.6.0 to 4.6.8 and 4.4.0 to 4.4.18 allows denial of service
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-96423.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-96423 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 382,795 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Description
X11 protocol dissector crash in 4.6.0 to 4.6.8 and 4.4.0 to 4.4.18 allows denial of service
Affected Products
wiresharkwiresharkDetection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2026-96423 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Disable the X11 protocol dissector if analyzing network traffic that does not require X11 packet decoding. For command-line analysis using tshark, disable the protocol at runtime: ``` tshark --disable-protocol x11 -r <capture_file> ``` For persistent user configuration, add the protocol identifier to the disabled protocols file: ``` mkdir -p ~/.config/wireshark echo "x11" >> ~/.config/wireshark/disabled_protos ``` In the Wireshark graphical interface, the dissector can be disabled by navigating to Analyze > Enabled Protocols, searching for "X11", unchecking the protocol entry, and clicking OK. Caveats: Disabling this dissector prevents Wireshark from decoding and analyzing X11 protocol…Source: Red Hat security advisory for CVE-2026-96423 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-96423 in your dependencies?
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