CVE-2026-9855 Custom Field Template <= 2.7.8 - Authenticated (Contributor+) SQL Injection via 'post_ID' Parameter

What is CVE-2026-9855?

CVE-2026-9855 is a medium-severity SQL injection vulnerability in hiroaki-miyashita Custom Field Template, published on 19 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

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.

Weakness: CWE-89

Which versions are affected by CVE-2026-9855?

How do I fix CVE-2026-9855?

No fix has been published for CVE-2026-9855 yet. Limit exposure of the affected software until one is available.

Use parameterised queries everywhere and never build SQL by joining strings. Upgrade affected software first; a web application firewall only buys time. More about SQL injection.

Is CVE-2026-9855 being exploited?

There is no known exploitation of CVE-2026-9855 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-fv9m-mw9j-43cg.