Percona ServerApplication · Percona
CVE-2020-26542
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 · uneditedAn issue was discovered in the MongoDB Simple LDAP plugin through 2020-10-02 for Percona Server when using the SimpleLDAP authentication in conjunction with Microsoft’s Active Directory, Percona has discovered a flaw that would allow authentication to complete when passing a blank value for the account password, leading to access against the service integrated with which Active Directory is deployed at the level granted to the authenticating account.
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 confidenceThe MongoDB Simple LDAP plugin for Percona Server contains an authentication bypass vulnerability when used with Microsoft Active Directory. The flaw allows authentication to succeed even when a blank password is provided, effectively bypassing the password verification mechanism and granting access with the privileges of the authenticating Active Directory account.
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
Percona ServerApplication
<= 2020-10-02CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify Percona Server versionRun 'mysqld --version' or check the installed Percona Server package to determine the version date (format is typically YYYY-MM-DD)Affected if The version date is 2020-10-02 or earlier
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Locate Simple LDAP plugin configurationCheck MySQL configuration files (my.cnf or mysqld.cnf) for entries containing 'auth_ldap_simple' or 'plugin-load-add' that load the Simple LDAP authentication pluginAffected if The Simple LDAP plugin is loaded via plugin-load-add or similar directive
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Verify Active Directory is the LDAP backendExamine LDAP configuration parameters in my.cnf or mysqld.cnf under sections related to auth_ldap_simple, specifically looking for LDAP server settings that connect to Microsoft Active Directory domain controllersAffected if The LDAP configuration points to Active Directory domain controllers (typically uses port 389 or 636, with domain-style DN strings)
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Test blank password authentication behaviorAttempt to authenticate to MySQL using an Active Directory user account with an empty or blank password string against the Simple LDAP pluginAffected if Authentication succeeds with a blank password when it should fail, indicating the bypass is present
A Percona Server installation dated 2020-10-02 or earlier with the Simple LDAP plugin enabled and configured for Active Directory is vulnerable to blank password authentication bypass.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataOrganizations using the Simple LDAP plugin with Active Directory should immediately review authentication configurations and consider implementing additional controls such as account lockout policies or multi-factor authentication until a patch is available from Percona.
Fix this in Percona Server
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing5.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-26542 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-26542 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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