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CVE Record

CVE-2026-21937: Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: DDL).

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: DDL). Supported versions that are affected are 8.0.0-8.0.44, 8.4.0-8.4.7 and 9.0.0-9.5.0. 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-2026-21937 is a denial-of-service issue in Oracle MySQL Server. An attacker who already has high privileges and network access can cause the database server to hang or repeatedly crash. The business risk is service outage, not data theft, based on the published CVSS impact.

Executive priority

Treat as a moderate operational resilience issue. Patch planning should be timely for critical databases, especially externally reachable systems, but urgency is lower than unauthenticated or data-exposure vulnerabilities because high privileges are required.

Technical view

Oracle reports the issue affects MySQL Server DDL handling in versions 8.0.0-8.0.44, 8.4.0-8.4.7, and 9.0.0-9.5.0. CVSS 3.1 is 4.9: network reachable, low complexity, high privileges required, no user interaction, availability impact only.

Likely exposure

Exposure is limited to organizations running affected MySQL Server versions where high-privileged database users can connect over supported network protocols. Internet exposure increases operational risk, but exploitation still requires high privileges.

Exploitation context

The source says the vulnerability is easily exploitable after obtaining high privileges. There is no KEV listing and no provided source indicating active exploitation or public exploit availability.

Researcher notes

Public details are limited to Oracle and CVE metadata. The affected component is Server: DDL. The stated impact is complete denial of service through hang or repeatable crash. No CWE, exploit details, or workaround specifics were provided in the source bundle.

Mitigation direction

  • Review Oracle’s January 2026 CPU guidance for the applicable MySQL Server update path.
  • Prioritize affected internet-accessible or business-critical MySQL servers.
  • Restrict network access to MySQL services to trusted administrative paths.
  • Review and reduce high-privileged MySQL accounts where operationally feasible.
  • Ensure database restart and failover procedures are current.

Validation and detection

  • Inventory MySQL Server versions across production, staging, and backup systems.
  • Compare versions against Oracle’s affected ranges.
  • Confirm whether Oracle’s CPU has been applied per vendor guidance.
  • Review privileged database accounts with network access.
  • Check monitoring for unexplained MySQL hangs, crashes, or repeated restarts.
Prepared
Confidence
high
Sources
3

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-2026-21937 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
2Source 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-2026-21937Attack 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 Server8.0.0, 8.4.0, 9.0.0Listed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.