Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Oracle confirms unauthenticated network reach over multiple protocols with no user interaction and DoS-only impact, so A:H with C:N/I:N and PR:N/UI:N are appropriate.
Primary rating from Vendor (oracle).
CVSS VectorVendor: oracle
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
1DescriptionCVE.org
Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: Connection Handling). Supported versions that are affected are MySQL Server: 8.4.0-8.4.9, 9.0.0-9.7.0; MySQL Cluster: 8.0.11-8.0.46, 8.4.0-8.4.9 and 9.0.0-9.7.0. Easily exploitable vulnerability allows unauthenticated 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 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
AnalysisAI
Remote unauthenticated denial-of-service in Oracle MySQL Server and MySQL Cluster (8.0.x, 8.4.x, and 9.0.0-9.7.0) allows network attackers to trigger a hang or repeatable crash of the database via the Server Connection Handling component. Oracle rates the issue as easily exploitable over multiple protocols with no authentication or user interaction, producing a complete availability loss (CVSS 7.5, A:H only). No public exploit identified at time of analysis and the issue is not listed in CISA KEV.
Technical ContextAI
The flaw is in the MySQL Server Connection Handling subsystem, the layer that accepts inbound client sessions over MySQL protocols (classic MySQL protocol on 3306, MySQL X Protocol on 33060, and in Cluster builds the NDB management/data ports). Per the CPE data (cpe:2.3:a:oracle_corporation:mysql_server and :mysql_cluster) both the standalone Server and the Cluster (NDB) distributions share this code path, which is why three release trains (8.0 Cluster, 8.4, and 9.x innovation) are all affected. No CWE was assigned by Oracle, but the symptom profile - unauthenticated network input causing a hang or deterministic crash with no confidentiality or integrity impact - is characteristic of CWE-400/CWE-617 class bugs (uncontrolled resource consumption or reachable assertion) in the pre-authentication handshake or connection state machine.
RemediationAI
Apply the fixes shipped in Oracle's June 2026 Critical Patch Update (https://www.oracle.com/security-alerts/cspujun2026.html); Oracle did not publish an exact fixed point release in the input data, so consult the CPU matrix for the specific 8.4.x, 9.7.x, and 8.0.x NDB build that supersedes the affected ranges (Patch available per vendor advisory; exact fix version to be confirmed from the CPU). Until patches are deployed, restrict network reachability of TCP 3306 and 33060 (and NDB management port 1186 plus data node ports for Cluster) to known application hosts via firewall or security group rules, place MySQL behind a bastion or VPN, and consider front-ending with a proxy such as ProxySQL or MySQL Router that can rate-limit or drop malformed handshakes - note these controls reduce exposure but do not eliminate risk from compromised application tier hosts. Enable connection monitoring and automatic restart (systemd Restart=on-failure or orchestrator-managed failover) so a repeatable crash does not cause prolonged outage, and avoid exposing MySQL directly to the internet under any circumstance.
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-37356