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CVE Record

CVE-2021-35638: 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 8.0.26 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-2021-35638 is a MySQL Server availability flaw. A highly privileged attacker who can reach MySQL over the network could cause the server to hang or crash repeatedly. The business impact is service disruption, not data theft or tampering based on the provided sources.

Executive priority

Treat as a planned reliability patch unless the database is internet-exposed or many privileged accounts exist. Prioritize systems supporting critical business services because successful exploitation can create complete denial of service.

Technical view

The vulnerability affects Oracle MySQL Server 8.0.26 and prior, in the Server: Optimizer component. CVSS 3.1 is 4.9, with network attack vector, low complexity, high privileges required, no user interaction, and high availability impact only.

Likely exposure

Exposure is limited to environments running MySQL Server 8.0.26 or earlier where high-privileged database users can connect over supported network protocols.

Exploitation context

The source data says the issue is easily exploitable by a high-privileged network attacker. It is not listed as KEV, and the provided sources do not show active exploitation.

Researcher notes

Public data identifies the vulnerable product, component, affected versions, CVSS vector, and impact, but does not describe root cause, proof of concept, indicators, or exploit telemetry. Avoid assuming confidentiality or integrity impact.

Mitigation direction

  • Apply Oracle's October 2021 Critical Patch Update guidance for MySQL Server.
  • Upgrade affected MySQL Server 8.0.26 and earlier deployments to vendor-supported patched releases.
  • Restrict network access to MySQL services to trusted administrative and application sources.
  • Review NetApp guidance if NetApp products in your environment embed or depend on MySQL.

Validation and detection

  • Inventory MySQL Server instances and record exact versions.
  • Flag MySQL Server 8.0.26 and earlier as affected.
  • Confirm administrative database accounts are limited and reviewed.
  • Check whether MySQL is reachable from untrusted networks or broad internal segments.
  • Monitor database service logs for repeated hangs, crashes, or unexplained restarts.
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-2021-35638 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-2021-35638Attack 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 Server8.0.26 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.