Auth bypass in Slim Seo

CVE-2026-16957

The Slim SEO WordPress plugin before 4.9.11 does not restrict a post-meta preview feature to posts the user is allowed to edit, verifying only read access, allowing users with the Contributor role to read arbitrary post meta, including protected and private keys, of published posts they do not own, including password-protected posts and posts of non-public post types.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 2.7 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.002 (7.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 7.7% 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-2026-16957: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

  • Slim Seo — versions 0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-16957?
CVE-2026-16957 is a low-severity vulnerability in Slim Seo, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 2.7/10. Published 2026-08-09.
How severe is CVE-2026-16957?
Low severity. CVSS v3 base score is 2.7 out of 10.