CVE-2026-21948: Oracle MySQL Server · Easily exploitable vulnerability allows high privileged attacker with network access via multiple
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.oracle/mysql-serverpkg:maven/com.oracle/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
1. Apply official patches from Oracle as soon as they become available to address this vulnerability directly. 2. Restrict network access to MySQL Server instances by implementing strict firewall rules and network segmentation, limiting access only to trusted administrative hosts. 3. Enforce the principle of least privilege by auditing and minimizing high-privileged accounts that can access MySQL over the network. 4. Implement strong authentication and monitoring for administrative access to detect and prevent unauthorized privilege escalation. 5. Deploy intrusion detection and prevention systems (IDPS) to monitor for unusual MySQL server behavior indicative of DoS attempts. 6. Regularly back up critical databases to enable rapid recovery in case of service disruption. 7. Conduct internal security awareness and training to reduce risks from insider threats who might exploit this vulnerability. 8. Use MySQL configuration best practices to harden the server and reduce attack surface, such as disabling unused protocols and services.
Description
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.0-8.0.44, 8.4.0-8.4.7 and 9.0.0-9.5.0. 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. CVSS 3.1 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).