CVE-2025-21522: Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Parser). Supported versions that are affected are 8.0.40 and prior, 8.4.3 and prior and 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
CSIRTS triage
- What
- Parser component vulnerability allowing low-privileged network-based attackers to cause unspecified impact.
- Who is affected
- MySQL Server versions 8.0.40 and earlier, 8.4.3 and earlier, or 9.1.0 and earlier with network access.
- Urgency
- Moderate; easily exploitable by low-privileged attackers, not yet exploited.
- Action
- Upgrade MySQL Server to a version after 8.0.40, 8.4.3, or 9.1.0.
AI-assisted analysis generated from the source advisory — verify against the original.
⚡ Watch MySQL Server
Get an email when a new MySQL Server advisory drops — max one per day, one-click unsubscribe.
Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21522
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Moderate exploitation riskCVE-2025-215221.0% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 61% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2025-21522 | coverage & exploitation status | NVD · CVE.org |
Recent advisories for MySQL Server product
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- mediumCVE-2025-21493: Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Security: Privil…msrc · 2026-08-06
- mediumCVE-2024-20966: Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supp…msrc · 2026-08-06
- mediumCVE-2025-21566: Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supp…msrc · 2026-08-06
- mediumCVE-2025-21504: Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supp…msrc · 2026-08-06
- mediumCVE-2025-21543: Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Packaging). Supp…msrc · 2026-08-06
- mediumCVE-2025-21536: Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supp…msrc · 2026-08-06
More from Microsoft Security Response Center
- lowCVE-2026-14673: PostgreSQL amcheck does not clear untrusted search path2026-08-11
- criticalCVE-2026-69836: Microsoft Entra ID Remote Code Execution Vulnerability2026-08-11
- mediumCVE-2026-53792: rsync < 3.5.0 Out-of-Bounds Read via Zero-Length Checksum Block2026-08-11
- highCVE-2026-70347: Windows Installer Elevation of Privilege Vulnerability2026-08-11
- highCVE-2026-64909: Microsoft Office Remote Code Execution Vulnerability2026-08-11