CVE-2026-77549: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-g4h7-m732-3278
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CVSS 9.0
CWE-93
Published
Advisory Summary

CVE-2026-77549 is a CRITICAL (CVSS 9.0) security vulnerability vulnerability (CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product uses crlf (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes crlf sequences from inputs.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-77549 at a Glance

CVE Identifier CVE-2026-77549
GHSA Identifier GHSA-g4h7-m732-3278
Severity CRITICAL
CVSS v3.1 Base Score 9.0
CWE Classification CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.0

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-77549

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-77549, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection'), where the product uses crlf (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes crlf sequences from inputs. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

References

NVD — CVE-2026-77549 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-77549
Software Release RELEASE
https://community.ui.com/releases/Security-Advisory-Bulletin-067/fc4a3488-7c43-4628-8bab-f715e96dbfc9

Frequently Asked Questions

What is CVE-2026-77549?
CVE-2026-77549 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection').
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-77549?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-77549?
CVE-2026-77549 has a CVSS v3.1 base score of 9.0 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2026-77549?
CVE-2026-77549 is classified under CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection') (The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.).
How can I check Maven dependencies for CVE-2026-77549?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-g4h7-m732-3278",
  "modified" : "2026-08-27T06:31:29Z",
  "published" : "2026-08-27T06:31:29Z",
  "aliases" : [ "CVE-2026-77549" ],
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-77549"
  }, {
    "type" : "WEB",
    "url" : "https://community.ui.com/releases/Security-Advisory-Bulletin-067/fc4a3488-7c43-4628-8bab-f715e96dbfc9"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-93" ],
    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-26T11:16:38Z"
  }
}