Mysql 5.5: CVE-2026-101789 affects MySQL Server, MySQL Cluster (Server: Optimizer)
Affects mysql-5.5Source GCVE Database
Not known to be exploited · CVSS 6.5 Medium.
Data as of 27 Oct 2026, 08:28 UTC
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 20 Oct 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 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10mariadbpkg:deb/ubuntu/mariadb?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10mysql-9.7pkg:deb/ubuntu/mysql-9.7?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSmariadbpkg:deb/ubuntu/mariadb?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSmysql-8.4pkg:deb/ubuntu/mysql-8.4?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSmariadbpkg:deb/ubuntu/mariadb?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSmysql-8.0pkg:deb/ubuntu/mysql-8.0?arch=source&distro=nobleOther 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
Oracle has released a Critical Patch Update in October 2026 that includes a fix for CVE-2026-101789. Users should apply the official Oracle patches promptly to mitigate this vulnerability. Oracle strongly recommends running actively-supported versions and applying security patches without delay. No alternative mitigations or workarounds are specified.
Description
CVE-2026-101789 is a security vulnerability affecting MySQL Server and MySQL Cluster, specifically the Server Optimizer component. It impacts multiple MySQL versions including 8.0, 8.4, and 9.7, as well as various Ubuntu-packaged versions of MySQL 5.5. The vulnerability was publicly disclosed in October 2026 and is classified as medium severity. Oracle has released a Critical Patch Update in October 2026 that addresses this and many other vulnerabilities across its product portfolio. Users are strongly advised to apply the available patches promptly to mitigate the risk.