How severe is CVE-2026-77549?

CVE-2026-77549 has a CVSS 3.x base score of 9.0, rated critical severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-77549 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-77549?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-77549 published?

CVE-2026-77549 was published on 2026-08-26 and last updated on 2026-08-28.

CVE-2026-77549

CVE-2026-77549 is a critical-severity vulnerability with a CVSS 3.x base score of 9.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-93.

Key facts

Severity: Critical (CVSS 3.x base score 9.0)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-93
Published: 2026-08-26
Last modified: 2026-08-28

Description

A malicious actor with access to the network and under certain conditions could exploit an Improper Neutralization of CRLF Sequences vulnerability found in certain devices running UniFi OS to bypass authentication to such UniFi OS devices or instances.

Frequently asked questions

What is CVE-2026-77549?: A malicious actor with access to the network and under certain conditions could exploit an Improper Neutralization of CRLF Sequences vulnerability found in certain devices running UniFi OS to bypass authentication to such UniFi OS devices or instances.
How severe is CVE-2026-77549?: CVE-2026-77549 has a CVSS 3.x base score of 9.0, rated critical severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-77549 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-77549?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-77549 published?: CVE-2026-77549 was published on 2026-08-26 and last updated on 2026-08-28.

References

https://community.ui.com/releases/Security-Advisory-Bulletin-067/fc4a3488-7c43-4628-8bab-f715e96dbfc9

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