Mysql 5.5: CVE-2026-101801 affects MySQL Server, MySQL Cluster (Server: Optimizer)
Affects mysql-5.5Source GCVE Database
Not known to be exploited · CVSS 4.9 Medium.
Data as of 27 Oct 2026, 08:28 UTC
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 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 security patches for this vulnerability as part of the October 2026 Critical Patch Update. Users of affected MySQL versions should apply these official patches immediately. Oracle strongly recommends remaining on actively supported versions and applying all security updates without delay to mitigate this and other vulnerabilities. No additional mitigation steps are indicated beyond patching.
Description
CVE-2026-101801 is a medium severity vulnerability affecting MySQL Server and MySQL Cluster, specifically the Server Optimizer component. It impacts multiple versions of MySQL including 8.0, 8.4, and 9.7, as well as various Ubuntu-packaged versions of MySQL 5.5. Oracle has included this vulnerability in its October 2026 Critical Patch Update, which contains numerous security patches across many Oracle products. Oracle strongly recommends applying the available security patches promptly to mitigate this and other vulnerabilities.