What is CVE-2026-86837?

CVE-2026-86837 is a medium-severity vulnerability in Bookly, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 5.3/10. Published 2026-09-25.

How severe is CVE-2026-86837?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Auth bypass in Bookly

CVE-2026-86837

The Bookly WordPress plugin before 28.3 does not properly verify a customer's identity before updating their stored details, allowing unauthenticated attackers who know a customer's primary identifier to overwrite that customer's stored personal information such as name, email and address.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published 2026-09-25 · last modified 2026-09-25.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (6.9th percentile), scored 2026-09-26.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 7th percentile — 6.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

The 30-day trend appears once there are two daily scores.

Affected products

Bookly

Weakness classification (CWE)

CWE-639 — Authorization Bypass Through User-Controlled Key

References

wpscan.com/vulnerability/5bfed7cf-5bf3-4a3b-a2b6-9f9d48f52fd5/ (technical-description, exploit, vdb-entry)

Frequently asked questions

What is CVE-2026-86837?: CVE-2026-86837 is a medium-severity vulnerability in Bookly, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 5.3/10. Published 2026-09-25.
How severe is CVE-2026-86837?: Medium severity. CVSS v3 base score is 5.3 out of 10.