CVE-2026-105061: WP Mailster cross-site scripting (XSS) vulnerability

high 7.1 published 2026-10-06

Affected versions: 1.9.0.0 and older
Fixed in: 1.9.1.0
Latest version: 1.9.2.0
Severity: High · CVSS 7.1
Active installs: 300+
Type: Cross-site scripting (XSS)

What an attacker needs

Access: None. No account or login is needed (per the CVSS score).
Interaction: It also needs someone on the site (often an admin) to click a link, open a page or submit a form the attacker prepared.

CVSS vector (score by Patchstack): CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L

What to do now

Update WP Mailster to 1.9.1.0 or newer (the latest is 1.9.2.0): 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 WP Mailster issue. With WP-CLI: wp plugin get wp-mailster --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

Unauthenticated Cross Site Scripting (XSS) in WP Mailster <= 1.9.0.0 versions.

Description from the CVE record, published by Patchstack (the CVE Numbering Authority), via the NVD entry for CVE-2026-105061.

References

NVD CVE-2026-105061 nvd.nist.gov
Patchstack advisory patchstack.com

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/wp-mailster (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.