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CVE-2026-4431

CRITICALCVSS 9.1/10EPSS 0.33%

Last modified

CVE-2026-4431 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. The Easy Post Submission plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the `create_post()` function in all versions up to, and including, 2.3.0. This is due to the `rbsm_submit_post` AJAX action being registered for unauthenticated users via `wp_ajax_nopriv_rbsm_submit_post` without any authorization checks when a `postId` parameter is supplied. EPSS estimates a 0.33% chance of exploitation in the next 30 days.

Description

The Easy Post Submission plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the `create_post()` function in all versions up to, and including, 2.3.0. This is due to the `rbsm_submit_post` AJAX action being registered for unauthenticated users via `wp_ajax_nopriv_rbsm_submit_post` without any authorization checks when a `postId` parameter is supplied. This makes it possible for unauthenticated attackers to modify the title, content, excerpt, categories, and tags of arbitrary posts, as well as change the post status to draft (effectively unpublishing them) via the 'postId' parameter.

Metrics

CVSS 3.1
9.1/10

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

EPSS Probability
0.33%

26.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
themerubyEasy Post Submission – Frontend Posting, Guest Publishing & Submit Content for WordPress<= 2.3.0

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-4431?
The Easy Post Submission plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the `create_post()` function in all versions up to, and including, 2.3.0. This is due to the `rbsm_submit_post` AJAX action being registered for unauthenticated users via `wp_ajax_nopriv_rbsm_submit_post` without any authorization checks when a `postId` parameter is supplied. This makes it possible for unauthenticated attackers to modify the title, content, excerpt, categories, and tags of arbitrary posts, as well as change the post status to draft (effectively unpublishing them) via the 'postId' parameter.
How severe is CVE-2026-4431?
CVE-2026-4431 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.33% probability of exploitation in the next 30 days.
How do I fix CVE-2026-4431?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST