CVE-2023-21868
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 · uneditedVulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.31 and prior. Easily exploitable vulnerability allows low privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.1 Base Score 6.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
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 · high confidenceVulnerability in MySQL Server Optimizer component (versions 8.0.31 and prior) allowing low-privileged attackers with network access to cause denial of service via crash or hang of the MySQL Server. Exploitable through multiple network protocols.
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>= 8.0.0, <= 8.0.31CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 installed MySQL versionRun query: SELECT VERSION(); or check with: mysql --version from command lineAffected if Version is 8.0.0 through 8.0.31 inclusive
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Verify MySQL network listening configurationCheck my.cnf or my.ini for bind-address setting, or run: SHOW VARIABLES LIKE 'bind_address';Affected if MySQL is bound to 0.0.0.0 or a routable IP address (not 127.0.0.1)
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Confirm network access exposureCheck if port 3306 (default MySQL) is open externally: netstat -tlnp | grep 3306 or nmap -p 3306 targetAffected if MySQL port is accessible from untrusted networks
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Review user privilege configurationRun: SELECT user, host, plugin FROM mysql.user WHERE user NOT IN ('mysql.infoschema','mysql.session','mysql.sys');Affected if Low-privileged users exist with network access (non-localhost hosts)
Environment is affected if running MySQL 8.0.0-8.0.31 with network access exposed to untrusted users, regardless of privilege level since even low-privileged accounts can trigger the DoS.
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.
dbcve · scopedApply Oracle Critical Patch Update or upgrade MySQL to version 8.0.32 or later. If immediate patching is not feasible, restrict network access to the MySQL server and enforce least-privilege access controls.
MySQL Server 8.0.32 or later (recommended: latest 8.0.x stable release)
- 1. Schedule a maintenance window for the MySQL server upgrade.
- 2. Back up all databases and configuration files before proceeding with the upgrade.
- 3. Stop the MySQL service: systemctl stop mysql or service mysql stop.
- 4. Update the MySQL repository and upgrade to version 8.0.32 or later using the package manager (yum update mysql-server or apt-get install mysql-server).
- 5. Start the MySQL service: systemctl start mysql or service mysql start.
- 6. Run mysql_upgrade to check and update system tables if needed: mysql_upgrade -u root -p.
- 7. Verify the MySQL version after upgrade: mysql -u root -p -e "SELECT VERSION();".
- 8. Test application connectivity and functionality before returning to production.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation4.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,504.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-21868 — 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-2023-21868 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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- 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