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CVE Record

CVE-2021-35626: 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-2021-35626 is a denial-of-service flaw in Oracle MySQL Server's optimizer. A highly privileged attacker with network access could make affected MySQL Server instances hang or crash repeatedly. It does not indicate data theft or modification, but it can disrupt applications that depend on MySQL availability.

Executive priority

Treat as a scheduled but concrete availability fix. It is not an emergency from the provided evidence, but affected production databases should be upgraded because successful abuse can cause complete service disruption.

Technical view

The issue affects Oracle MySQL Server 8.0.26 and prior, in the Server: Optimizer component. The CVSS 3.1 vector is AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H, meaning network-reachable, low complexity, high privileges required, and availability-only impact.

Likely exposure

Exposure is mainly MySQL Server 8.0.26 or earlier instances reachable over network protocols by users with high database privileges. Internet exposure increases operational risk, but privilege requirements limit broad unauthenticated exploitation.

Exploitation context

The CVE is not listed as CISA KEV in the provided bundle, and no provided source states active exploitation. The realistic scenario is misuse by a privileged user or an attacker who already obtained high-privilege MySQL access.

Researcher notes

Evidence supports a high-privilege, network-accessible denial-of-service condition in MySQL Server optimizer. The bundle does not provide CWE, root-cause details, exploit indicators, or active exploitation evidence. Avoid assuming broader Oracle or NetApp product impact without vendor confirmation.

Mitigation direction

  • Apply Oracle CPU guidance or a supported MySQL release beyond affected versions.
  • Check NetApp guidance if MySQL is embedded or bundled in NetApp products.
  • Restrict MySQL network access to trusted hosts and administrative paths.
  • Review and minimize high-privilege MySQL accounts.
  • Monitor MySQL stability until remediation is complete.

Validation and detection

  • Inventory all MySQL Server instances and record exact versions.
  • Flag Oracle MySQL Server 8.0.26 and earlier for remediation.
  • Confirm MySQL listeners are not exposed beyond required networks.
  • Review privileged database accounts and recent administrative access.
  • Check logs and monitoring for repeated crashes or hangs.
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-2021-35626 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-2021-35626Attack 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.