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CVE Record

CVE-2021-2164: Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer).

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.23 and prior. Easily exploitable vulnerability allows high 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 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).

MediumCVSS 4.9Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This flaw can let a highly privileged user crash or hang a vulnerable MySQL Server, causing a complete denial of service. It does not indicate data theft or data alteration. Business urgency depends on whether MySQL 8.0.23 or earlier remains in use and whether privileged database access is tightly controlled.

Executive priority

Treat as a targeted availability risk rather than a broad data breach risk. Prioritize remediation where MySQL supports critical services, privileged access is widely shared, or database downtime would disrupt revenue, operations, or customer-facing systems.

Technical view

CVE-2021-2164 affects Oracle MySQL Server Optimizer in supported versions 8.0.23 and prior. The CVSS 3.1 score is 4.9 with network attack vector, low complexity, high privileges required, no user interaction, and high availability impact only.

Likely exposure

Exposure is most likely in environments still running Oracle MySQL Server 8.0.23 or earlier, including packaged or appliance-delivered MySQL dependencies. Systems reachable by privileged database users over network protocols are the primary concern.

Exploitation context

The provided sources do not show CISA KEV listing or active exploitation. Exploitation requires high privileges and network access, so risk is concentrated around compromised privileged accounts, shared administrative access, and poorly segmented database networks.

Researcher notes

The source bundle does not provide exploit details, CWE mapping, or proof-of-concept evidence. The key constraints are PR:H, AV:N, and A:H. Validation should focus on versioning, patch provenance, privileged access paths, and operational crash telemetry.

Mitigation direction

  • Apply Oracle April 2021 CPU guidance or later vendor-supported MySQL updates.
  • Update affected Fedora packages if MySQL came from Fedora advisories.
  • Check NetApp guidance if MySQL is embedded in NetApp-managed products.
  • Restrict privileged MySQL access to trusted administrative networks and accounts.
  • Monitor vulnerable servers for repeated crashes, hangs, or unexpected restarts.

Validation and detection

  • Inventory MySQL Server versions and identify 8.0.23 or earlier instances.
  • Confirm installed builds include Oracle April 2021 CPU or vendor-equivalent fixes.
  • Review privileged MySQL accounts and remove unnecessary administrative access.
  • Check database logs and service monitors for repeated optimizer-related crashes.
  • Validate downstream vendor exposure for Fedora and NetApp-managed deployments.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2021-2164 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
4.9 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
4.9CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H1.23.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

4.9Medium
CVSS 3.1 vector shape for CVE-2021-2164Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Oracle CorporationMySQL Server8.0.23 and priorListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.