dbcve.org
YubiserverApplication · Debian

CVE-2015-0842

CRITICAL · 9.8 CVSS v3.1 Published 2025-06-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
yubiserver before 0.6 is prone to SQL injection issues, potentially leading to an authentication bypass.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

yubiserver before version 0.6 contains SQL injection vulnerabilities that allow attackers to manipulate SQL queries, potentially bypassing authentication mechanisms. The critical CVSS score of 9.8 reflects the severe impact of unauthorized access to what should be a secure authentication system.

MitigationUpgrade yubiserver to version 0.6 or later which addresses the SQL injection vulnerabilities. If upgrading is not immediately possible, implement input validation and parameterize all database queries as an interim measure.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
YubiserverApplication
Affected:= 0.2-2= 0.5-2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if yubiserver is installed
    Look for yubiserver files in common locations: /usr/share/yubiserver, /var/www/yubiserver, or check for the package using your system package manager (dpkg -l | grep yubiserver or apt list --installed 2>/dev/null | grep yubi)
    Affected if yubiserver is found installed on the system
  2. Determine the installed yubiserver version
    Check the package version using dpkg -l yubiserver or apt-cache policy yubiserver; alternatively, look for a VERSION or version file in the installation directory
    Affected if the version is 0.2-2 or 0.5-2 (Debian package notation) or any version before 0.6
  3. Verify the database backend is configured
    Examine yubiserver configuration files (commonly config.php, config.ini, or similar in the installation directory) for database connection parameters (db_host, db_user, db_password, database name)
    Affected if a database backend (MySQL, PostgreSQL, or SQLite) is configured and connected to yubiserver
  4. Check if SQL-based authentication is in use
    Look in the yubiserver configuration for auth_backend settings; if it points to a SQL database (mysql, pgsql, sqlite) rather than file-based or other methods, the SQL injection is applicable
    Affected if SQL database authentication is enabled in the configuration

The system is affected if yubiserver version 0.2-2 or 0.5-2 (or any version before 0.6) is installed with a SQL database backend configured for authentication.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade yubiserver to version 0.6 or later which addresses the SQL injection vulnerabilities. If upgrading is not immediately possible, implement input validation and parameterize all database queries as an interim measure.

Recommended fix Moderate confidence

yubiserver 0.6 or later

  1. 1. Backup your current yubiserver installation and database before proceeding
  2. 2. Download yubiserver version 0.6 or later from the official repository
  3. 3. Review the migration/upgrade notes in the release documentation
  4. 4. Replace the existing yubiserver files with the new version
  5. 5. Run any database migration scripts provided in the upgrade
  6. 6. Verify the installation by testing authentication functionality
  7. 7. Confirm the SQL injection vulnerability is resolved by attempting to reproduce the original vulnerability (if you have the original proof-of-concept)
Caveat Review release notes for version 0.6 - potential configuration or database schema changes may require adjustment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Yubiserver Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,820
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2015-0842 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data