CVE-2026-107508: Ultimate Multisite path traversal / file read vulnerability
high 8.6 published 2026-10-14
- Affected versions
- older than 2.17.2
- Fixed in
- 2.17.2
- Latest version
- 2.18.0
- Severity
- High · CVSS 8.6
- Active installs
- 100+
- Type
- Path traversal / file read
What an attacker needs
- Access: None. No account or login is needed.
CVSS vector (score by CISA ADP): CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
What to do now
- Update Ultimate Multisite to 2.17.2 or newer (the latest is 2.18.0): Dashboard → Updates, or Plugins → “update now”.
- If you cannot update right away, deactivate it until you can.
- Turn on auto-updates for it: Plugins → “Enable auto-updates” on its row.
- Not sure which version you run? Check your version against every known Ultimate Multisite issue.
With WP-CLI:
wp plugin get ultimate-multisite --field=version. - If you ran an affected version and something looks off (new admin users, spam pages, redirects), run the free scan below.
The advisory
The Ultimate Multisite WordPress plugin before 2.17.2 does not validate a user-supplied value used to select a file to include, allowing unauthenticated attackers to include and read arbitrary local files, including the WordPress configuration file.
References
- NVD CVE-2026-107508 nvd.nist.gov
- WPScan advisory wpscan.com
Related
Ran an affected version? Check your site for signs of a hack
The free scan reads the public side of your site and looks for spam pages, hidden redirects, injected scripts and blacklist entries. No login, no install, about a minute.
Where this data comes from
- CVE record, score and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
- Versions and install counts: wordpress.org/plugins/ultimate-multisite (Plugins API), fetched 2026-11-04.
- The summary, “what an attacker needs” and “what to do” sections are our plain-English reading of the record and the plugin's release history; the quoted description is the record's own text. Spot an error? Email Daniel.