Jetpack 14.5 - 16.1.2 - Reflected to Stored Cross-Site Scripting via Reader Repost Parameters

2026-09-03 00:00
Anonymous

Strategic Overview

Status
Patched in 14.5.1
Affected Plugin
Jetpack – WP Security, Backup, Speed, & Growth
Affected Version
14.5 – 16.1.2 · 17 branches
CVSS
6.1Medium
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE pending
View all Jetpack – WP Security, Backup, Speed, & Growth vulnerabilities

At a glance

This record tracks a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Jetpack WordPress plugin, affecting versions 14.5 – 16.1.2 · 17 branches. It carries a CVSS score of 6.1 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 14.5.1; sites on affected versions should update now. Disclosed September 2026.

Vulnerability Overview

The Jetpack – WP Security, Backup, Speed, & Growth plugin for WordPress is vulnerable to Cross-Site Scripting in versions 14.5 through 16.1.2 via the Reader repost initializer in the block editor bundles. The initializer reads the url, title, text, comment_content, and comment_author query parameters and interpolates them into block attributes without escaping or sanitization before calling resetEditorBlocks(). On WordPress 7.1, only title and url were demonstrated to persist into live executable markup; the other parameters did not produce a stored executable sink. This makes it possible for unauthenticated attackers to inject arbitrary web scripts into a post via a crafted link that, when opened and saved by a user with the unfiltered_html capability (administrator or editor by default), stores the payload in post_content where it executes in the browser of every subsequent visitor to the published post. The Blocks module must be active and the site must be Jetpack-connected or in offline mode for the vulnerable bundle to be enqueued.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Jetpack 14.5 – 16.1.2 · 17 branches carries this weakness at resetEditorBlocks(), and reaching it takes a caller who can reach the endpoint. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Jetpack the fix is 14.5.1: builds 14.5 – 16.1.2 · 17 branches are affected, anything from 14.5.1 onward is not.

Remediation

Update to one of the following versions, or a newer patched version: 14.5.1, 14.6.1, 14.7.1, 14.8.1, 14.9.2, 15.0.3, 15.1.2, 15.2.1, 15.3.2, 15.4.1, 15.5.1, 15.6.1, 15.7.2, 15.8.1, 15.9.2, 16.0.2, 16.1.3

How does WordSec protect against this?

The attempt arrives as an ordinary request to Jetpack: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Jetpack 14.5.1 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.wordfence.com/threat-intel/vulnerabilities/id/eda9ae01-cdc4-43e0-8a4c-1ec365939fa8

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