MySQLDatabase / datastore · Oracle
CVE-2021-2481
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 8.0.26 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's Optimizer component allows low-privileged attackers with network access to cause a denial of service via hang or repeatable crash. The vulnerability affects MySQL 8.0.26 and prior versions.
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
MySQLDatabase / datastore
>= 8.0, < 8.0.26
FedoraOperating system
= 33= 34= 35all versionsall versionsCVSS 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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Check installed MySQL Server versionRun `mysql --version` from command line, or connect to MySQL and execute `SELECT VERSION();`Affected if Version output shows 8.0.x where x is less than 26 (for example, 8.0.25, 8.0.20, etc.)
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Confirm MySQL server is running and accessible over networkCheck if MySQL is listening on a network port: run `netstat -tlnp | grep 3306` or `ss -tlnp | grep 3306` to see if MySQL is bound to 0.0.0.0 or a specific IP addressAffected if MySQL is bound to a network interface (not localhost only) and is reachable from network addresses
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Verify low-privilege user access existsCheck for existing MySQL users with limited privileges by running `SELECT user, host, plugin FROM mysql.user;` as a privileged userAffected if There are MySQL users with network access (host not being localhost) who have only basic privileges and could exploit the Optimizer component
If your MySQL version is 8.0.x where x is less than 26 AND the server is accessible over the network, you are likely affected by this vulnerability.
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 · scoped8.0.26
Apply Oracle's critical patch update for MySQL 8.0.27 or later, or upgrade to a supported MySQL version. Test in a non-production environment before deploying to ensure application compatibility.
MySQL Server 8.0.27 or later
- 1. Back up all MySQL databases before performing the upgrade
- 2. Stop the MySQL Server service
- 3. For Oracle MySQL: Upgrade to MySQL Server 8.0.27 or later by following Oracle's upgrade documentation
- 4. For Fedora systems: Run 'sudo dnf update mysql' or 'sudo dnf update mariadb' to apply the security fix
- 5. Start the MySQL Server service
- 6. Verify the MySQL version using 'mysql --version' to confirm the upgrade was successful
- 7. Test application connectivity to ensure normal operation
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in MySQL
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,648.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-2481 — 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-2021-2481 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