SQL Injection in Hiroaki-Miyashita Custom Field Template

CVE-2026-9855

The Custom Field Template plugin for WordPress is vulnerable to generic SQL Injection via the 'post_ID' parameter in all versions up to, and including, 2.7.8 due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query. This makes it possible for authenticated attackers, with contributor-level access and above, to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database. The capability check via current_user_can('edit_post', $id) is bypassable because WordPress internally casts $id to an integer for the permission evaluation while the full unsanitized string is preserved and passed to the SQL sink, and a valid nonce — which is also required — can be legitimately obtained by any Contributor-level user from the post edit screen.

Vulnerability class: SQL Injection

Published · last modified .

CVSS v3 metric

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

EPSS exploit prediction

EPSS: 0.006 (47.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 47.7% 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-2026-9855: held from 0.006 to 0.006.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-9855?
CVE-2026-9855 is a medium-severity vulnerability in Hiroaki-Miyashita Custom Field Template, classified under SQL Injection. CVSS score: 6.5/10. Published 2026-09-19.
How severe is CVE-2026-9855?
Medium severity. CVSS v3 base score is 6.5 out of 10.