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CVE Record

CVE-2021-35635: 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 is a denial-of-service flaw in Oracle MySQL Server's optimizer. An attacker already holding high privileges and network access could make the database hang or crash repeatedly. The main business risk is service interruption, not data theft or tampering, based on the supplied CVSS details.

Executive priority

Treat as a medium-priority availability risk. It deserves timely remediation on production databases, especially critical systems, but the high-privilege requirement lowers broad emergency urgency absent exploitation evidence.

Technical view

CVE-2021-35635 affects MySQL Server 8.0.26 and prior in the Server: Optimizer component. It is network reachable, low complexity, requires high privileges, and needs no user interaction. Successful exploitation can cause a complete availability impact through hangs or repeatable crashes.

Likely exposure

Exposure is most likely where MySQL Server 8.0.26 or earlier remains deployed and high-privileged accounts can connect over network-accessible MySQL protocols. Internet exposure is not required, but privileged internal, application, or administrative access paths matter.

Exploitation context

The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The vulnerability is described as easily exploitable, but only by a high-privileged attacker with network access.

Researcher notes

Do not assume confidentiality or integrity impact from the supplied data. Focus assessment on version, optimizer component exposure, privileged access paths, and operational resilience. Fixed-version detail is not included in the bundle, so defer to Oracle guidance.

Mitigation direction

  • Upgrade MySQL Server according to Oracle CPU October 2021 or later vendor guidance.
  • Prioritize externally reachable or business-critical MySQL instances first.
  • Restrict MySQL network access to trusted application and administration sources.
  • Reduce and review high-privileged MySQL accounts.
  • Monitor database availability for unexplained hangs or repeated crashes.

Validation and detection

  • Inventory MySQL Server versions and flag 8.0.26 or prior.
  • Confirm whether affected instances received Oracle CPU October 2021 fixes or later.
  • Review privileged MySQL account access and network reachability.
  • Check monitoring and logs for recurring MySQL crashes or hangs.
  • Verify NetApp advisory relevance where NetApp-managed products include MySQL exposure.
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-2021-35635 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-2021-35635Attack 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.