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MySQL Server EUVDEUVD-2026-106127

| CVE-2026-101726 MEDIUM
Improper Access Control (CWE-284)
2026-10-20 secalert_us@oracle.com GHSA-v53p-mg94-5822
6.5
CVSS 3.1 · Vendor: oracle
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain low-privileged MySQL credentials
  2. Delivery
    Connect over network via supported protocol
  3. Exploit
    Send crafted C API request
  4. Execution
    Trigger hang or repeatable crash
  5. Impact
    Complete denial of service

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Access control enforcement
MITRE ATT&CK

1 technique across 1 tactic: Defense Evasion

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires an authenticated MySQL account with at least low-level privileges (PR:L) and network reachability to the server over one of the supported MySQL protocols; it targets the C API component of affected MySQL Server (8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1) and MySQL Cluster (8.0.0-8.0.49, 8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1) builds. No user interaction and no special non-default configuration are required per the CVSS vector. The primary limiting factor is the authentication requirement: an attacker must already hold valid, even if minimally privileged, database credentials, so instances that restrict network exposure and limit low-trust accounts face substantially lower real-world risk. Impact is confined to availability (service hang or complete crash); no data is read or altered.

Impact

This is a moderate-priority availability vulnerability, not a critical one. The CVSS 3.1 base score of 6.5 (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) reflects a network-reachable, low-complexity flaw requiring only low-level privileges and no user interaction, with impact limited exclusively to availability (C:N/I:N/A:H) - a complete denial of service via hang or repeatable crash, with no data confidentiality or integrity exposure. Oracle characterizes it as 'easily exploitable,' which is consistent with AC:L. However, several key risk-amplifying signals are absent: there is no CISA KEV listing, no public proof-of-concept, and no EPSS score provided in the input, so there is no evidence of active or imminent widespread exploitation. The PR:L requirement meaningfully limits exposure - an attacker needs valid (even if minimally privileged) authenticated access to the database, so an authenticated-but-low-trust user or a compromised application credential is the realistic threat model, not an anonymous internet attacker. Net assessment: real but not urgent. Prioritize via Oracle's quarterly patching cycle rather than emergency out-of-band response, and give higher priority where MySQL instances are exposed to large pools of low-trust authenticated users (multi-tenant or shared-hosting deployments). No conflicting signals were detected between the CVSS vector and the description; both agree on network vector, low privilege, and availability-only impact.

Exploit ScenarioDerived

An authenticated low-privileged user - or an attacker who has obtained a limited MySQL account through credential theft or a compromised application - connects over the network via one of the supported protocols and sends crafted input that exercises a defect in the C API component, causing the server to hang or repeatedly crash and producing a complete denial of service. Because privileges required are low and attack complexity is low, exploitation is straightforward once network and credential access exist, though no public exploit code has been identified at time of analysis.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 21, 2026

Denial of service in Oracle MySQL Server and MySQL Cluster allows low-privileged authenticated users with network access to hang or repeatedly crash the service via the C API component. Affected builds are MySQL Server 8.4.0-8.4.12, 9.7.0-9.7.3, and 26.7.0-26.7.1, plus MySQL Cluster 8.0.0-8.0.49, 8.4.0-8.4.12, 9.7.0-9.7.3, and 26.7.0-26.7.1. No public exploit identified at time of analysis, and impact is limited to availability with a CVSS 3.1 base score of 6.5.

RemediationAI

Apply the Oracle Critical Patch Update October 2026 fixes referenced at https://www.oracle.com/security-alerts/cpuoct2026.html; the exact first-fixed release versions are not included in the provided data, so use the advisory's MySQL Server and MySQL Cluster patch matrix to select the correct upgrade. Until patching is complete, restrict network access to MySQL listeners to trusted application hosts and management networks, remove or tightly limit low-privilege accounts that do not need network or C API access, and monitor for unexpected server restarts or repeated crashes. These compensating controls reduce exposure but can break legitimate clients if access lists or accounts are too narrow, and they do not replace the vendor fix.

Affected VersionsENISA

MySQL Server 8.4.0-8.4.12
MySQL Server 9.7.0-9.7.3
MySQL Server 26.7.0-26.7.1
MySQL Cluster 8.4.0-8.4.12
MySQL Cluster 8.0.0-8.0.49
MySQL Cluster 9.7.0-9.7.3
MySQL Cluster 26.7.0-26.7.1

Affected Packages

euvd mysql_cluster no fix
euvd mysql_server no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The issue resides in Oracle MySQL's C API component, which provides programmatic access to MySQL Server and MySQL Cluster over supported network protocols. The supplied data does not name a specific CWE, and the precise memory-safety or logic defect is not disclosed in the input, but the CVSS vector (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) describes a low-complexity, network-reachable, authenticated denial-of-service condition that can cause a hang or repeatable crash. Because confidentiality and integrity impacts are None, the defect should be treated as an availability-only bug rather than a data-exposure or code-execution issue; the PR:L authentication requirement is the main barrier, since an attacker must already hold valid low-privilege database credentials. No CPE strings were provided, so affected products are identified from the Oracle MySQL advisory ranges.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (oracle) PRIMARY 6.5 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vuln.today AI 6.5 MEDIUM

Network-reachable and low-complexity per Oracle's 'easily exploitable,' but requires a valid low-privileged account (PR:L); impact is availability-only DoS, so C:N/I:N/A:H.

3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Red Hat 6.5 MEDIUM

Primary rating from Vendor (oracle).

CVSS VectorVendor: oracle

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionCVE.org

Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: C API). Supported versions that are affected are MySQL Server: 8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1; MySQL Cluster: 8.0.0-8.0.49, 8.4.0-8.4.12, 9.7.0-9.7.3 and 26.7.0-26.7.1. Easily exploitable vulnerability allows low privileged attacker with network access via multiple protocols to compromise MySQL Server, MySQL Cluster. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server, MySQL Cluster. CVSS 3.1 Base Score 6.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).

Threat Intelligence Overview

EPSS Score
0.4%
Top 66% exploitable
Prevalence
Ubiquitous
MySQL is one of the most widely deployed databases worldwide
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.4%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Vendor StatusVendor

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