CVE-2025-21566
MEDIUMDescription
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 9.1.0 and prior. Easily exploitable vulnerability allows low 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 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).
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 50% of all known CVEs.
References
Related Vulnerabilities
Other CWE-732 (Incorrect Permission Assignment for Critical Resource) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2011-3923 | Critical | 9.8 | 89% | - | Fix |
| CVE-2018-15379 | Critical | 9.8 | 86% | - | - |
| CVE-2018-1000207 | High | 7.2 | 64% | - | - |
| CVE-2023-32986 | High | 8.8 | 61% | - | - |
| CVE-2021-44521 | Critical | 9.1 | 55% | - | Fix |
| CVE-2018-13374 | Medium | 4.3 | 38% | KEV + Ransom | Fix |
Common questions
How do I fix CVE-2025-21566?
No published fix for CVE-2025-21566 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2025-21566 being actively exploited?
Not that we know of. CVE-2025-21566 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.69% is the estimated probability that it will be exploited in the next 30 days. That is higher than 50% of all scored CVEs.
How severe is CVE-2025-21566?
CVE-2025-21566 has a CVSS v3 base score of 6.5, rated moderate. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-03.