Resource exhaustion in Oracle MySQL Server

CVE-2025-21521

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Thread Pooling). Supported versions that are affected are 8.0.39 and prior, 8.4.2 and prior and 9.0.1 and prior. Easily exploitable vulnerability allows unauthenticated 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 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).

EPSS: 0.011 (64.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-21521?
CVE-2025-21521 is a high-severity vulnerability in Oracle MySQL Server, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2025-01-21.
How severe is CVE-2025-21521?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2025-21521 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.