CVE-2025-21521: mysql server DoS — Fix

Description

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).

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-770 CWE-770

Affected Products

Vendor	Product	Versions
oracle	mysql_server	8.0.0 — 8.0.39
oracle	mysql_server	8.4.0 — 8.4.2
oracle	mysql_server	9.0.0 — 9.0.1

References

Advisories & Patches

https://www.oracle.com/security-alerts/cpujan2025.html

Other References

https://security.netapp.com/advisory/ntap-20250124-0010/

Frequently Asked Questions

What is 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). It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2025-21521? +

CVE-2025-21521 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-21521? +

CVE-2025-21521 affects products from oracle, specifically: mysql_server. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-21521? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2025-21521