Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessObtain high-privileged MySQL credentials
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DeliveryConnect over network via supported protocol
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ExploitSubmit crafted query mishandled by Optimizer
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ExecutionTrigger server hang or repeatable crash
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ImpactComplete denial of service of MySQL Server/Cluster
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 session as a high-privileged MySQL account (PR:H) with network reachability to the database over one of MySQL's supported protocols; it does not require user interaction or a non-default configuration. The decisive limiting factor is the high-privilege requirement - only a trusted, highly privileged database user (or an attacker who has already obtained such credentials) can trigger the flaw - which sharply narrows the realistic attacker population to insiders or those who have already compromised a privileged account. Affected deployments are 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; the impact is limited to availability (service hang/crash) with no data confidentiality or integrity consequence. |
| Impact | This is a moderate-severity, availability-only denial-of-service flaw in the MySQL Server/Cluster Optimizer component, rated CVSS 3.1 4.9 (AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H). The signals are internally consistent and point to a lower real-world priority than the 'easily exploitable' language in Oracle's description might suggest: exploitation requires PR:H (high privileges - an existing authenticated account with substantial database privileges), which is the single biggest limiting factor, while AC:L and AV:N indicate that an already-privileged attacker can trigger it easily over the network. Impact is confined to availability (C:N/I:N/A:H) - a hang or repeatable crash (complete DoS) - with no confidentiality or integrity exposure and no scope change (S:U). No EPSS score, CISA KEV listing, or public POC is present in the provided data, so there is no evidence of active exploitation or widespread automated targeting; this reads as a high-CVSS-product (MySQL) but genuinely moderate-risk issue because the privilege barrier means the attacker must already be a trusted high-privilege DB user. Note the SSVC/EPSS/KEV inputs are absent rather than low - do not treat their absence as proof of safety. The main practical risk is a malicious or compromised privileged account, or a privileged application service account, causing service outages. |
| Exploit ScenarioDerived | A high-privileged MySQL user (e.g. a compromised application service account or malicious DBA) connects over the network via a supported protocol and issues a specially crafted query that the Optimizer mishandles, causing the server to hang or crash and producing a complete denial of service for MySQL Server/Cluster. No public exploit code was identified in the provided data, so any attack would require the adversary to independently develop the triggering query. Because only availability is affected, the outcome is service disruption rather than data theft or tampering. |
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Alert meAnalysisAIv1 – Oct 21, 2026
A denial-of-service flaw in the Optimizer component of MySQL Server and MySQL Cluster lets a high-privileged, network-connected database account hang or repeatedly crash the server, with CVSS 3.1 base score 4.9 (availability-only). Affected releases are MySQL Server 8.4.0-8.4.12, 9.7.0-9.7.3 and 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 and 26.7.0-26.7.1. Exploitation requires an authenticated session using a highly privileged account (PR:H) over MySQL's supported protocols, so the realistic threat is insiders or attackers who already hold privileged credentials; no public exploit code or confirmed active exploitation was identified at time of analysis.
RemediationAI
Apply the Oracle CPU October 2026 updates for MySQL Server and MySQL Cluster, upgrading each installation to a release at or above the fixed builds published in https://www.oracle.com/security-alerts/cpuoct2026.html - that advisory is the only source carrying the exact patched version numbers, so confirm the target build against it before upgrading rather than assuming a version not stated in this data (no vendor-released patch version was independently confirmed in the supplied input). Until patching is complete, reduce exposure by auditing and trimming accounts holding high privileges: revoke unnecessary SUPER, SYSTEM_VARIABLES_ADMIN and other privileged grants, and remove accounts that do not genuinely need optimizer-affecting capabilities - the trade-off is loss of administrative functionality for those users. Restrict network reachability to the database to application and administrative subnets through firewall rules or bind-address changes, which limits who can obtain a high-privileged session but does not help against a malicious insider already inside the trust boundary. Where privileged access cannot be constrained, enable per-account connection limits and resource groups, and monitor for repeated server restarts or hung queries originating from privileged accounts, accepting that this is detection rather than prevention. No public exploit code was identified at time of analysis, so exploit-based prioritization is not a justification for delay, but the PR:H requirement means patching can be scheduled around maintenance windows with the privileged-account hardening above as an interim control.
Affected VersionsENISA
Affected Packages
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 vulnerability sits in the Server: Optimizer component, the query-planning subsystem of MySQL Server that parses SQL statements, evaluates access paths, and produces execution plans; MySQL Cluster (NDB) bundles the same server-side optimizer surface. Because the flaw is reachable via multiple protocols with network access (AV:N), a crafted statement submitted by a logged-in, high-privileged user can drive the optimizer into a state that hangs or repeatedly crashes the server process, yielding a complete denial of service. The CVSS 3.1 vector (AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H) confines impact to availability only - no confidentiality or integrity effect and no scope change - and the PR:H metric is the decisive limiter, since only trusted, highly privileged database users (or someone who has already compromised such credentials) can reach the vulnerable code path. Oracle does not publish a CWE class for this advisory, and no CVE-specific root-cause details (such as the particular optimizer transformation or plan-selection routine involved) were released; the EUVD and NVD records reference only the October 2026 Oracle Critical Patch Update advisory.
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Severity by source
AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Network-reachable (AV:N) and low-complexity (AC:L) but requires an existing high-privileged DB account (PR:H); impact is availability-only (A:H, C:N/I:N) with no scope change.
Primary rating from Vendor (oracle).
CVSS VectorVendor: oracle
DescriptionCVE.org
Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: Optimizer). 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 high 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 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).
Threat Intelligence Overview
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.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
Oracle MySQL through 5.5.52, 5.6.x through 5.6.33, and 5.7.x through 5.7.15; MariaDB before 5.5.51, 10.0.x before 10.0.2
MySQL 5.5.19 and possibly other versions, and MariaDB 5.5.28a and possibly other versions, when configured to assign the
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Pluggable Auth). Rated high severity
sql/password.c in Oracle MySQL 5.1.x before 5.1.63, 5.5.x before 5.5.24, and 5.6.x before 5.6.6, and MariaDB 5.1.x befor
In Spring Framework, versions 5.2.x prior to 5.2.3, versions 5.1.x prior to 5.1.13, and versions 5.0.x prior to 5.0.16,
Heap-based buffer overflow in Oracle MySQL 5.5.19 and other versions through 5.5.28, and MariaDB 5.5.28a and possibly ot
Stack-based buffer overflow in the acl_get function in Oracle MySQL 5.5.19 and other versions through 5.5.28, and 5.1.53
Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due
mysqld_safe in Oracle MySQL through 5.5.51, 5.6.x through 5.6.32, and 5.7.x through 5.7.14; MariaDB; Percona Server befo
Oracle MySQL before 5.7.3, Oracle MySQL Connector/C (aka libmysqlclient) before 6.1.3, and MariaDB before 5.5.44 use the
HUSTOJ online judge has a path traversal vulnerability enabling arbitrary file access on the competition server.
Integer overflow in the EVP_EncodeUpdate function in crypto/evp/encode.c in OpenSSL before 1.0.1t and 1.0.2 before 1.0.2
EUVD-2026-106202
GHSA-cj49-48fc-hjr8
NVD
CVE.org
EPSS
Exploit-DB