CVE-2026-97257: Simple Event Planner PHP object injection vulnerability
high 8.8 published 2026-10-05 · updated 2026-10-06
- Affected versions
- 1.5.7 and older
- Fixed in
- 1.5.8
- Latest version
- 1.5.8
- Severity
- High · CVSS 8.8
- Active installs
- 1,000+
- Type
- PHP object injection
What an attacker needs
- Access: A low-level account on the site, such as a subscriber or customer (per the CVSS score).
CVSS vector (score by Patchstack): CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
What to do now
- Update Simple Event Planner to 1.5.8 or newer: 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 Simple Event Planner issue.
With WP-CLI:
wp plugin get simple-event-planner --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
Deserialization of Untrusted Data vulnerability in PressTigers Simple Event Planner simple-event-planner allows Object Injection.This issue affects Simple Event Planner: from n/a through 1.5.7.
References
- NVD CVE-2026-97257 nvd.nist.gov
- Patchstack advisory patchstack.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/simple-event-planner (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.