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CVE Record

CVE-2021-2427: 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 8.0.25 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

CVE-2021-2427 is a denial-of-service flaw in Oracle MySQL Server's optimizer. An attacker who already has high privileges and network access can make affected servers hang or crash repeatedly, disrupting applications that depend on MySQL. The cited impact is availability only, not data theft or tampering.

Executive priority

Treat this as a moderate availability risk. It requires high privileges, which limits opportunistic exposure, but a compromised administrator account could repeatedly interrupt critical MySQL-backed services. Prioritize patch verification on production and externally reachable database environments.

Technical view

Oracle reports MySQL Server 8.0.25 and prior are affected in the Server: Optimizer component. CVSS 3.1 is 4.9 with network attack vector, low complexity, high privileges required, no user interaction, unchanged scope, and high availability impact only.

Likely exposure

Exposure is mainly MySQL Server 8.0.25 and prior reachable over network protocols by highly privileged users or compromised privileged accounts. Risk is higher for production databases supporting critical services, multi-tenant environments, or systems where privileged database access is broadly distributed.

Exploitation context

The source bundle says the flaw is easily exploitable after high-privilege access is available. It does not provide evidence of public exploitation, proof-of-concept availability, or active exploitation. CISA KEV status is false in the supplied data.

Researcher notes

The available evidence identifies Oracle MySQL Server, component Server: Optimizer, affected through 8.0.25. No CWE is listed. The record supports denial-of-service impact only. Do not assume confidentiality, integrity, exploit-in-the-wild, or a specific fixed version beyond vendor advisory guidance.

Mitigation direction

  • Review Oracle July 2021 CPU guidance for applicable MySQL Server patches.
  • Upgrade affected MySQL Server 8.0.25 and prior systems per vendor guidance.
  • Review NetApp guidance where MySQL is present in NetApp-supported environments.
  • Restrict privileged MySQL accounts to trusted administrators and required network paths.
  • Prioritize availability protections for business-critical MySQL-backed services.

Validation and detection

  • Inventory MySQL Server versions and flag 8.0.25 and prior.
  • Confirm production MySQL instances are mapped to business-critical applications.
  • Review privileged MySQL accounts and network access paths.
  • Check change records for Oracle July 2021 CPU or later vendor remediation.
  • Review database logs and monitoring for unexplained hangs or repeat crashes.
Prepared
Confidence
high
Sources
4

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-2021-2427 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
3Source 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-2021-2427Attack 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 Server8.0.25 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.