CVE-2026-5402: TLS protocol dissector heap overflow in Wireshark 4.6.0 to 4.6.4 allows denial of service and possible code ex

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HIGH 8.8UPGRADE

CVE-2026-5402 is a high-severity flaw (CVSS 8.8) affecting wireshark. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

TLS protocol dissector heap overflow in Wireshark 4.6.0 to 4.6.4 allows denial of service and possible code execution

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.4% (top 67%)
CISA exploited list	No
Weakness	CWE-122
Published	2026-04-30
Last modified	2026-10-26

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

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-30 07:16 UTCPublished CVE record published
2026-10-26 00:10 UTCUpdated Record last modified

wireshark wireshark UPGRADE

Affected: >= 4.6.0 and <= 4.6.4

Fixed in: newer than 4.6.4

Safe to downgrade to: a release before 4.6.0

1. Check installed version

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

2. UPGRADE to newer than 4.6.4 (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 4.6.0 (Debian / Ubuntu)

apt-cache madison wireshark sudo apt install wireshark=<VERSION_BEFORE_4.6.0> 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_4.6.0> 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.

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-2026-5402?

wireshark: upgrade to newer than 4.6.4. Exact commands for each OS are on this page.

Is CVE-2026-5402 being exploited?

CVE-2026-5402 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-2026-5402 affect?

CVE-2026-5402 affects wireshark. Severity is high (CVSS 8.8). TLS protocol dissector heap overflow in Wireshark 4.6.0 to 4.6.4 allows denial of service and possible code execution

How urgent is CVE-2026-5402?

Priority 44/100. High severity; Public exploit reference

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References

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