Auth bypass in Backup Migration

CVE-2026-18216

The Backup Migration WordPress plugin before 2.1.7 does not properly restrict a post-restore automatic login mechanism, allowing a user who administers one site of a multisite network to obtain a long-lived authenticated session as an administrator of another site in the same network, without credentials and bypassing two-factor authentication.

Vulnerability class: Broken Authentication

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.005 (40.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 40.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-18216: held from 0.003 to 0.005.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

  • Backup Migration — versions 0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-18216?
CVE-2026-18216 is a medium-severity vulnerability in Backup Migration, classified under Improper Authentication. CVSS score: 6.5/10. Published 2026-08-15.
How severe is CVE-2026-18216?
Medium severity. CVSS v3 base score is 6.5 out of 10.