LiveActive security incident?Get immediate response
CVE Record

CVE-2021-35643: 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
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-35643 is a denial-of-service issue in Oracle MySQL Server's optimizer. A highly privileged user with network access to MySQL could make the server hang or repeatedly crash. The business impact is service outage, not data theft or data modification based on the provided sources.

Executive priority

Treat as a targeted availability risk. Prioritize internet-reachable, business-critical, and shared MySQL systems first, especially where administrative database access is broadly available.

Technical view

Oracle identifies the affected component as MySQL Server: Optimizer. Supported MySQL Server versions 8.0.26 and prior are affected. 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 where MySQL Server 8.0.26 or earlier remains in use and highly privileged database accounts can connect over network-accessible MySQL protocols.

Exploitation context

The sources describe the issue as easily exploitable by a high-privileged attacker with network access. The CVE is not listed as KEV in the provided bundle, and no cited source states active exploitation.

Researcher notes

Evidence supports availability-only impact and high privilege requirements. The bundle does not include root cause details, exploit proof, or a named fixed version, so validation should focus on version state, vendor patch status, and access boundaries.

Mitigation direction

  • Apply Oracle's October 2021 CPU or later MySQL security guidance.
  • Upgrade affected MySQL Server 8.0.26 and prior systems if vendor guidance provides a fixed release.
  • Restrict MySQL network access to trusted hosts and services.
  • Review and minimize highly privileged MySQL accounts.
  • Check NetApp guidance if MySQL is bundled in NetApp-managed products.

Validation and detection

  • Inventory MySQL Server versions and flag 8.0.26 and prior.
  • Confirm Oracle CPU or later vendor security updates are applied.
  • Review network exposure for MySQL listener access.
  • Audit highly privileged MySQL accounts and recent administrative logins.
  • Check monitoring for unexplained MySQL hangs or repeated 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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2021-35643 mapping review

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

Open ATT&CK lookup
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-2021-35643Attack 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.