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CVE Record

CVE-2021-2357: 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 8.0.25 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-2021-2357 can let a highly privileged user crash or hang MySQL Server, causing a complete denial of service. It does not indicate data theft or data modification. Business urgency depends on whether affected MySQL instances support critical services and whether privileged database access is tightly controlled.

Executive priority

Treat as a maintenance-priority availability issue. Accelerate remediation for production databases supporting revenue, authentication, customer portals, or operational workflows. Lower urgency may be reasonable for isolated, noncritical instances with tightly controlled privileged access.

Technical view

Oracle describes a MySQL Server Optimizer vulnerability affecting supported versions 8.0.25 and prior. 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 8.0.25 or earlier is reachable over the network by privileged users, service accounts, or applications. Internet exposure increases operational risk, but exploitation still requires high privileges according to the source bundle.

Exploitation context

The bundle says the issue is easily exploitable by a high-privileged attacker with network access via multiple protocols. It does not state public exploitation, and KEV status is false. Evidence supports denial-of-service risk, not confidentiality or integrity compromise.

Researcher notes

The provided sources identify product, component, affected version range, CVSS vector, and impact, but do not include root-cause detail, proof-of-concept status, or exact exploit mechanics. Avoid assuming broader MySQL forks or unsupported versions are affected without vendor confirmation.

Mitigation direction

  • Identify MySQL Server instances running 8.0.25 or earlier.
  • Apply Oracle July 2021 CPU or later vendor-approved MySQL updates.
  • Follow Fedora or NetApp advisories for downstream packaged deployments.
  • Restrict privileged MySQL access to trusted networks and accounts.
  • Review service-account privileges and remove unnecessary high privileges.

Validation and detection

  • Confirm MySQL Server version and package source on each host.
  • Verify applicable Oracle, Fedora, or NetApp update guidance was applied.
  • Check database logs for unexplained hangs, crashes, or repeated restarts.
  • Review network paths allowing privileged access to MySQL services.
  • Confirm privileged accounts are limited and actively owned.
Prepared
Confidence
high
Sources
6

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-2021-2357 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
5Source 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-2021-2357Attack 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 Server8.0.25 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.