CVE-2026-109979: Auth Bypass (CVSS 4.3)

Description

The Related Posts for WordPress plugin for WordPress is vulnerable to Sensitive Information Exposure in versions up to, and including, 3.0.0 via the 'rp4wp_create_link' parameter of the hidden 'rp4wp_link_related' admin page. The handle_create_link() handler verifies the nonce and that the current user can edit the parent post, but never checks that the attacker-supplied child post ID is one the user is allowed to read; LinkRepository::insert() stores the arbitrary child ID without validation, and ManageLinks::render() later calls LinkRepository::get_children() in its no-extra-args fast path, which falls through to array_map('get_post', $child_ids) — bypassing read_private_posts/read_post capability checks — and then echoes esc_html($child->post_title) in the parent's editor meta box. This makes it possible for authenticated attackers, with Contributor-level access and above, to read the titles of arbitrary non-public posts (drafts, pending, private, future, trashed) authored by higher-privileged users by linking those post IDs to a draft they own and then reading the resulting meta box.

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CVSS v3.1 Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0030

Probability of exploitation

0.22%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Other References

https://plugins.trac.wordpress.org/browser/related-posts-for-wp/tags/3.0.0/src/Admin/LinkScreen/Page.php#L164 https://plugins.trac.wordpress.org/browser/related-posts-for-wp/tags/3.0.0/src/Admin/MetaBox/ManageLinks.php#L98 https://plugins.trac.wordpress.org/browser/related-posts-for-wp/tags/3.0.0/src/Links/LinkRepository.php#L310 https://plugins.trac.wordpress.org/browser/related-posts-for-wp/tags/3.0.0/src/Links/LinkRepository.php#L86 https://plugins.trac.wordpress.org/changeset/3757484/related-posts-for-wp/trunk/src/Admin/LinkScreen/Page.php https://plugins.trac.wordpress.org/changeset?reponame=&old=3757484%40related-posts-for-wp&new=3757484%40related-posts-for-wp https://www.wordfence.com/threat-intel/vulnerabilities/id/3ab9af6a-bfe7-4da5-8e60-b20f38cbab36?source=cve

Frequently Asked Questions

What is CVE-2026-109979? +

The Related Posts for WordPress plugin for WordPress is vulnerable to Sensitive Information Exposure in versions up to, and including, 3.0.0 via the 'rp4wp_create_link' parameter of the hidden 'rp4wp_link_related' admin page. The handle_create_link() handler verifies the nonce and that the current user can edit the parent post, but never checks that the attacker-supplied child post ID is one the user is allowed to read; LinkRepository::insert() stores the arbitrary child ID without validation, and ManageLinks::render() later calls LinkRepository::get_children() in its no-extra-args fast path, which falls through to array_map('get_post', $child_ids) — bypassing read_private_posts/read_post capability checks — and then echoes esc_html($child->post_title) in the parent's editor meta box. This makes it possible for authenticated attackers, with Contributor-level access and above, to read the titles of arbitrary non-public posts (drafts, pending, private, future, trashed) authored by higher-privileged users by linking those post IDs to a draft they own and then reading the resulting meta box. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-109979? +

CVE-2026-109979 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0030, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-109979? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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