CVE-2025-21559: Oracle MySQL Server · Missing Authentication
Affects Oracle MySQL ServerSource CVE Database V5
Not known to be exploited · CVSS 5.5 Medium.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 54% 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:L/A:HExploitation evidence
Disclosed: evidence found.
CVE published 21 Jan 2025
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 2026-10-26.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Mysqlmysql/mysql-serverpkg:deb/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
European organizations should implement the following specific mitigations: 1) Restrict network access to MySQL servers by enforcing strict firewall rules and network segmentation, allowing only trusted hosts and administrators to connect. 2) Enforce the principle of least privilege by auditing and minimizing high privilege accounts on MySQL servers. 3) Monitor MySQL server logs and network traffic for unusual activity indicative of exploitation attempts, such as repeated crashes or unauthorized data changes. 4) Prepare to apply vendor patches promptly once released; track Oracle security advisories closely. 5) Consider deploying Web Application Firewalls (WAFs) or database activity monitoring tools that can detect and block suspicious queries or commands. 6) Conduct regular security assessments and penetration tests focusing on database security to identify privilege escalation risks. 7) Implement robust backup and recovery procedures to restore data integrity in case of unauthorized modifications or service disruptions.
Description
Vulnerability in the MySQL Server product of Oracle MySQL (component: InnoDB). Supported versions that are affected are 8.0.40 and prior, 8.4.3 and prior and 9.1.0 and prior. 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 as well as unauthorized update, insert or delete access to some of MySQL Server accessible data. CVSS 3.1 Base Score 5.5 (Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:H).