CVE-2026-54400: A malicious actor with access to the network and high privileges could exploit an Improper Access Control vuln

Q: How do I fix CVE-2026-54400?

unifi access: upgrade to 4.2.29. Exact commands for each OS are on this page.

Q: Is CVE-2026-54400 being exploited?

CVE-2026-54400 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-54400 affect?

CVE-2026-54400 affects unifi access. Severity is critical (CVSS 9.1). A malicious actor with access to the network and high privileges could exploit an Improper Access Control vulnerability found in UniFi Access Application to escalate privileges on the host device.

Q: How urgent is CVE-2026-54400?

Priority 43/100. Critical severity

This month

CRITICAL 9.1UPGRADE

CVE-2026-54400 is a critical-severity flaw (CVSS 9.1) affecting unifi access. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A malicious actor with access to the network and high privileges could exploit an Improper Access Control vulnerability found in UniFi Access Application to escalate privileges on the host device.

Why this priority

Critical severity

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	None
EPSS exploit chance	0.5% (top 56%)
CISA exploited list	No
Weakness	CWE-284
Published	2026-07-02
Last modified	2026-10-25

Publisher (CNA): HackerOne · Vendor: ui

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-02 15:17 UTCPublished CVE record published
2026-10-25 21:10 UTCUpdated Record last modified

ui unifi access UPGRADE

Affected: < 4.2.29

Fixed in: 4.2.29

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy unifi-access || rpm -q unifi-access || unifi-access --version

2. UPGRADE to 4.2.29 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade unifi-access

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade unifi-access

Note

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

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-2026-54400?

unifi access: upgrade to 4.2.29. Exact commands for each OS are on this page.

Is CVE-2026-54400 being exploited?

CVE-2026-54400 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-2026-54400 affect?

CVE-2026-54400 affects unifi access. Severity is critical (CVSS 9.1). A malicious actor with access to the network and high privileges could exploit an Improper Access Control vulnerability found in UniFi Access Application to escalate privileges on the host device.

How urgent is CVE-2026-54400?

Priority 43/100. Critical severity

Software pages

Ubiquiti vulnerabilities

Related CVEs

CVE-2026-50748 CRITICAL 9.9 UPGRADE A malicious actor with access to the network and low privileges could exploit an Improper Input Validation vul
CVE-2026-55117 HIGH 8.6 UPGRADE A malicious actor with access to the network could exploit a Path Traversal vulnerability found in UniFi Acces

References

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