CVE-2026-96423: X11 protocol dissector crash in 4.6.0 to 4.6.8 and 4.4.0 to 4.4.18 allows denial of service

Routine

MEDIUM 5.5UPGRADE

CVE-2026-96423 is a medium-severity flaw (CVSS 5.5) affecting wireshark. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

X11 protocol dissector crash in 4.6.0 to 4.6.8 and 4.4.0 to 4.4.18 allows denial of service

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.1% (top 97%)
CISA exploited list	No
Weakness	CWE-122, CWE-125
Published	2026-09-29
Last modified	2026-10-14

Publisher (CNA): GitLab Inc. · Vendor: wireshark

Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-29 10:17 UTCPublished CVE record published
2026-10-14 04:19 UTCUpdated Record last modified

wireshark wireshark UPGRADE

Affected: >= 4.4.0 and < 4.4.19 · >= 4.6.0 and < 4.6.9

Fixed in: 4.4.19, 4.6.9

Safe to downgrade to: a release before 4.4.0

1. Check installed version

apt-cache policy wireshark || rpm -q wireshark || wireshark --version

2. UPGRADE to 4.4.19 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade wireshark

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade wireshark

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 4.4.0 (Debian / Ubuntu)

apt-cache madison wireshark sudo apt install wireshark=<VERSION_BEFORE_4.4.0> sudo apt-mark hold wireshark

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list wireshark sudo dnf downgrade wireshark-<VERSION_BEFORE_4.4.0> sudo dnf versionlock add wireshark

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Advisories and coverage

Official advisories

Amazon Linux 2 ALAS: ALAS2-2026-4006 (important): wireshark 2026-10-24

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-96423?

wireshark: upgrade to 4.4.19, 4.6.9. Exact commands for each OS are on this page.

Is CVE-2026-96423 being exploited?

CVE-2026-96423 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-96423 affect?

CVE-2026-96423 affects wireshark. Severity is medium (CVSS 5.5). X11 protocol dissector crash in 4.6.0 to 4.6.8 and 4.4.0 to 4.4.18 allows denial of service

How urgent is CVE-2026-96423?

Priority 25/100. Public exploit reference

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References

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