Security readout for executives and security teams
Plain-English summary
CVE-2026-77549 is a critical UniFi OS flaw that may let an unauthenticated network attacker bypass login controls under specific conditions. Successful exploitation could compromise confidentiality, integrity, and availability of an affected device or instance. The supplied sources do not identify precise vulnerable versions or confirm exploitation in the wild.
Executive priority
Treat this as an urgent validation and remediation task because authentication bypass could enable broad device compromise. Prioritize externally or broadly reachable UniFi OS management surfaces. Escalate any confirmed affected system, but avoid declaring compromise solely from product presence because vulnerable versions and exploitation indicators are absent from the supplied evidence.
Technical view
UniFi OS improperly neutralizes CRLF sequences (CWE-93). Under certain unspecified conditions, a network-accessible, unauthenticated attacker may bypass authentication. CVSS 3.1 rates it 9.0 with high complexity, changed scope, and high confidentiality, integrity, and availability impacts. No user interaction is required.
Likely exposure
Exposure exists where a genuinely affected UniFi OS device or instance is reachable from an attacker-controlled network. The bundle lists several Ubiquiti product families but marks their supplied version entries as unaffected, so it does not establish precise affected models, releases, or configurations.
Exploitation context
The attack is network-based, requires no privileges or user interaction, and has high attack complexity. The necessary conditions are not described in the bundle. The CVE is not listed as KEV, and the supplied sources provide no evidence of active exploitation or public exploit availability.
Researcher notes
Key unknowns are the vulnerable release ranges, prerequisite conditions, fixed releases, and compromise indicators. The affected-product records supplied as version "0" with default status "unaffected" are insufficient for exposure matching. Researchers should use the vendor bulletin as the authoritative source and avoid inferring exploitability from the CVSS score alone.
Mitigation direction
- Review Ubiquiti Security Advisory Bulletin 067 for confirmed affected versions and vendor-prescribed remediation.
- Apply applicable vendor updates after testing them against operational requirements.
- Restrict UniFi OS management access to trusted administrative networks until remediation is confirmed.
- Avoid assuming listed product families are vulnerable without matching vendor-supported version information.
Validation and detection
- Inventory UniFi OS devices, instances, models, and installed software versions.
- Compare each inventory record with the affected-version details in Ubiquiti Bulletin 067.
- Confirm management interfaces are inaccessible from untrusted networks.
- Verify applicable vendor updates installed successfully and remain present after reboot.
- Review authentication and administrative logs for unexplained access, while recognizing no indicators are supplied.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-93: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-77549 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H2.26UbiquitiVulnerability scoring details
Base CVSS 3.1 score
9CriticalVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://community.ui.com/releases/Security-Advisory-Bulletin-067/fc4a3488-7c43-4628-8bab-f715e96dbfc9CVE reference, Ubiquiti
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of CRLF Sequences
Improper Neutralization of CRLF Sequences represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.