CVE-2026-21964: 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
Not known to be exploited · CVSS 4.9 Medium.
Data as of 25 Oct 2026, 19:02 UTC
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 20 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 2026-10-25.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Oracle CorporationMySQL Server | Affected
| Fixed in– |
Mavencom.mysql/mysql-serverpkg:maven/com.mysql/mysql-serverOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
To mitigate CVE-2026-21964, European organizations should prioritize the following actions: 1) Apply official patches from Oracle as soon as they become available to remediate the vulnerability in affected MySQL Server versions. 2) Restrict network access to MySQL servers by implementing strict firewall rules and network segmentation to limit exposure to trusted hosts and administrative personnel only. 3) Enforce the principle of least privilege by reviewing and minimizing the number of users with high privileges on MySQL servers. 4) Monitor MySQL server logs and system behavior for signs of unusual hangs or crashes that could indicate exploitation attempts. 5) Implement robust authentication and access controls to prevent unauthorized privilege escalation. 6) Consider deploying failover and high availability configurations to reduce downtime impact in case of service disruption. 7) Conduct regular security audits and vulnerability assessments focusing on database infrastructure. 8) Educate system administrators about the risks and signs of exploitation related to this vulnerability to enhance detection and response capabilities.
Description
CVE-2026-21964 is a medium severity vulnerability in Oracle MySQL Server affecting versions 8.0.0 through 8.0.44, 8.4.0 through 8.4.7, and 9.0.