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CVE Record

CVE-2021-35636: 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

This flaw can let a highly privileged network user make vulnerable MySQL Server instances hang or crash repeatedly. The documented impact is availability loss only, not data theft or tampering. It matters most where MySQL supports critical applications and privileged database access is broadly available.

Executive priority

Treat this as a maintenance-priority availability risk, not an emergency based on the supplied evidence. Prioritize critical databases, internet-reachable administration paths, and systems with many privileged database users.

Technical view

CVE-2021-35636 affects Oracle MySQL Server Optimizer in supported versions 8.0.26 and prior. The CVSS 3.1 vector is AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H, scoring 4.9. A high-privileged attacker with network access through multiple protocols may trigger a complete denial of service.

Likely exposure

Exposure is limited to MySQL Server 8.0.26 and earlier where high-privileged users can connect over the network. Systems embedding or packaging MySQL should be checked against vendor advisories, including NetApp where applicable.

Exploitation context

The provided sources do not report active exploitation, and the CVE is not listed as KEV in the bundle. Exploitation requires high privileges, but the attack complexity is low once those privileges and network access exist.

Researcher notes

Public details identify the affected component and impact but not a CWE, root cause, or exploit technique. Avoid assuming broader impact than denial of service. Validation should focus on version, patch state, privilege boundaries, and vendor-packaged MySQL dependencies.

Mitigation direction

  • Apply Oracle's October 2021 CPU or a later MySQL security update.
  • Upgrade MySQL Server beyond affected 8.0.26 and prior versions.
  • Check appliance or platform vendor advisories for bundled MySQL exposure.
  • Restrict privileged MySQL accounts to trusted administrators and networks.
  • Review database availability monitoring for crash or hang alerts.

Validation and detection

  • Inventory MySQL Server versions across production and managed platforms.
  • Confirm affected systems are patched or upgraded past 8.0.26.
  • Verify privileged MySQL accounts are necessary, named, and restricted.
  • Check whether any vendor appliances include vulnerable MySQL builds.
  • Review operational logs for unexplained MySQL 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-2021-35636 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-2021-35636Attack 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.