Security readout for executives and security teams
Plain-English summary
This critical UniFi OS flaw could let an unauthenticated attacker who can reach a vulnerable device or instance bypass login controls. Successful exploitation could expose sensitive information, permit unauthorized changes, and disrupt service. The supplied sources do not identify exact affected versions or confirm exploitation in the wild.
Executive priority
Treat as an immediate verification and remediation priority. First identify reachable UniFi OS management systems, then use Ubiquiti's advisory to confirm affected versions and apply supported remediation. Escalate systems exposed to untrusted networks.
Technical view
CVE-2026-77550 is a CWE-93 CRLF neutralization flaw in certain UniFi OS devices or instances. Its CVSS 3.1 score is 10.0, with network access, low complexity, no privileges, and no user interaction. The vector reports changed scope and high confidentiality, integrity, and availability impact.
Likely exposure
Highest concern applies to UniFi OS management services reachable from untrusted networks. The bundle lists multiple Ubiquiti product families, but their version entries are ambiguous and marked default unaffected. Determine exposure from Ubiquiti's advisory rather than treating every listed product as vulnerable.
Exploitation context
The supplied bundle does not establish active exploitation, and KEV is false. The CVSS vector indicates a remotely reachable, unauthenticated, low-complexity path without user interaction, making confirmed vulnerable systems high-priority targets even without evidence of exploitation.
Researcher notes
The record describes authentication bypass through improper CRLF neutralization but provides no affected-version ranges, fixed releases, technical root-cause detail, or public exploit evidence. The listed version value "0" and default-unaffected status make product-level conclusions unreliable without the vendor bulletin.
Mitigation direction
- Review Ubiquiti Security Advisory Bulletin 067 for affected releases and vendor-prescribed remediation.
- Apply the vendor-supported update or mitigation identified for each confirmed vulnerable system.
- Restrict UniFi OS management access to trusted administrative networks while remediation is pending.
- Avoid assuming listed product families are vulnerable without matching their releases to vendor guidance.
Validation and detection
- Inventory UniFi OS devices and server instances, including installed software versions.
- Compare each version and product against Ubiquiti Security Advisory Bulletin 067.
- Identify management interfaces reachable from internet-facing or otherwise untrusted networks.
- After remediation, verify installed versions and confirm management access restrictions remain effective.
- Review relevant authentication and administrative logs for unexplained access or configuration changes.
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-2026-77550 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
- 10 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/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:L/PR:N/UI:N/S:C/C:H/I:H/A:H3.96UbiquitiVulnerability scoring details
Base CVSS 3.1 score
10CriticalVector: CVSS:3.1/AV:N/AC:L/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.