CVE-2026-19349: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-4vx7-c7qw-2vx4
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CVSS 9.8
CWE-305
Published
Advisory Summary

CVE-2026-19349 is a CRITICAL (CVSS 9.8) security vulnerability vulnerability (CWE-305: Authentication Bypass by Primary Weakness) affecting Software libraries in the Maven ecosystem. The weakness occurs when the authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-19349 at a Glance

CVE Identifier CVE-2026-19349
GHSA Identifier GHSA-4vx7-c7qw-2vx4
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-305: Authentication Bypass by Primary Weakness
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.8

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

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

How to Fix CVE-2026-19349

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-2026-19349, 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-305: Authentication Bypass by Primary Weakness, where the authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error. 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

Lemonldap::NG::Portal versions from 2.0.0 before 2.16.9, from 2.17.0 before 2.21.5, from 2.22.0 before 2.23.3 for Perl allow authentication bypass via an OAuth2 state parameter stored as an SSO session in the GitHub and LinkedIn backends. Before redirecting to the identity provider, extractFormInfo() creates the state session with the positional call `getApacheSession( undef, 1, 0, 'GitHubState' )`. getApacheSession() takes a session id followed by a named argument hash, so the trailing arguments become that hash, `kind` defaults to SSO, and the state is written to the global session storage as a regular SSO session. Its identifier is handed to the unauthenticated visitor as the state parameter of the redirection URL. Any visitor who reaches the GitHub or LinkedIn endpoint can replay that identifier as a session cookie and obtain a valid SSO session without authenticating. The session holds neither _user nor authenticationLevel, which the shipped bootstrap configuration accepts because it grants virtual hosts a "default => accept" access rule; deployments whose rules test the user or require an authentication level are less exposed. Only configurations with the GitHub or LinkedIn authentication module enabled are affected.

References

NVD — CVE-2026-19349 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-19349
gitlab.ow2.org/lemonldap-ng/lemonl... WEB
https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/releases/v2.16.9
gitlab.ow2.org/lemonldap-ng/lemonl... WEB
https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/releases/v2.21.5
gitlab.ow2.org/lemonldap-ng/lemonl... WEB
https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/releases/v2.23.3
Software Security Information SECURITY
http://www.openwall.com/lists/oss-security/2026/08/16/2

Frequently Asked Questions

What is CVE-2026-19349?
CVE-2026-19349 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-305: Authentication Bypass by Primary Weakness.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-19349?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-19349?
CVE-2026-19349 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-19349?
CVE-2026-19349 is classified under CWE-305: Authentication Bypass by Primary Weakness (The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.).
How can I check Maven dependencies for CVE-2026-19349?
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-4vx7-c7qw-2vx4",
  "modified" : "2026-08-17T18:31:12Z",
  "published" : "2026-08-16T15:30:24Z",
  "aliases" : [ "CVE-2026-19349" ],
  "details" : "Lemonldap::NG::Portal versions from 2.0.0 before 2.16.9, from 2.17.0 before 2.21.5, from 2.22.0 before 2.23.3 for Perl allow authentication bypass via an OAuth2 state parameter stored as an SSO session in the GitHub and LinkedIn backends.\n\nBefore redirecting to the identity provider, extractFormInfo() creates the state session with the positional call `getApacheSession( undef, 1, 0, 'GitHubState' )`. getApacheSession() takes a session id followed by a named argument hash, so the trailing arguments become that hash, `kind` defaults to SSO, and the state is written to the global session storage as a regular SSO session. Its identifier is handed to the unauthenticated visitor as the state parameter of the redirection URL.\n\nAny visitor who reaches the GitHub or LinkedIn endpoint can replay that identifier as a session cookie and obtain a valid SSO session without authenticating. The session holds neither _user nor authenticationLevel, which the shipped bootstrap configuration accepts because it grants virtual hosts a \"default => accept\" access rule; deployments whose rules test the user or require an authentication level are less exposed. Only configurations with the GitHub or LinkedIn authentication module enabled are affected.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-19349"
  }, {
    "type" : "WEB",
    "url" : "https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/releases/v2.16.9"
  }, {
    "type" : "WEB",
    "url" : "https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/releases/v2.21.5"
  }, {
    "type" : "WEB",
    "url" : "https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/releases/v2.23.3"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2026/08/16/2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-305" ],
    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-16T14:16:54Z"
  }
}