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VulnerabilityPublished

CVE-2026-21937: Easily exploitable vulnerability allows high 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.

Affects Oracle MySQL ServerSource CVE Database V5

0

Not known to be exploited · CVSS 4.9 Medium.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 3.1 base score
4.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 34% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 20 Jan 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Oracle CorporationMySQL ServerAffected
  • >=8.0.0 <=8.0.44
  • >=8.4.0 <=8.4.7
  • >=9.0.0 <=9.5.0
Fixed in–
Mavencom.oracle/mysql-serverpkg:maven/com.oracle/mysql-serverOther threatsAffected
  • =8.0.0
  • =8.4.0
  • =9.0.0
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

1. Restrict network access to MySQL servers strictly to trusted administrators and necessary application servers using firewalls and network segmentation. 2. Enforce the principle of least privilege by limiting high privilege accounts and regularly auditing user permissions to reduce the attack surface. 3. Monitor MySQL server logs and network traffic for unusual activity that could indicate exploitation attempts or instability. 4. Prepare incident response plans specifically for MySQL service disruptions to minimize downtime. 5. Stay informed on Oracle’s security advisories and apply patches or updates immediately once they are released for this vulnerability. 6. Consider deploying MySQL high availability solutions such as clustering or replication to mitigate the impact of potential DoS attacks. 7. Use network-level protections such as intrusion detection/prevention systems (IDS/IPS) to detect and block suspicious traffic targeting MySQL protocols. 8. Regularly back up databases to ensure data availability in case of service interruptions.

Description

CVE-2026-21937 is a medium severity vulnerability in Oracle MySQL Server versions 8.0.0 through 8.0.44, 8.4.0 through 8.4.7, and 9.0.

References

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