WordPress <= 6.9.1 - Unauthenticated Blind Server-Side Request Forgery via XML-RPC Pingback Discovery

2026-03-10 00:00

Strategic Overview

Status: Patched in 6.8.4
Affected Core: WordPress 6.9
Affected Version: 6.8 – 6.9.1 · 2 branches
CVSS: 5.8Medium
Weakness type: CWE-918 · Server-Side Request Forgery (SSRF)
CVE: CVE pending

At a glance

This record tracks a medium-severity Server-Side Request Forgery (SSRF) vulnerability in the WordPress 6.9 WordPress release line, affecting 6.8 – 6.9.1 · 2 branches. It carries a CVSS score of 5.8 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 6.8.4; sites on affected versions should update now. Disclosed March 2026, reported by sibwtf.

Vulnerability Overview

WordPress core is vulnerable to Blind Server-Side Request Forgery in all versions up to and including 6.9.1. This is due to the `WP_HTTP_IXR_Client` class using `wp_remote_post()` instead of the safer `wp_safe_remote_post()` when making outgoing XML-RPC pingback requests. This makes it possible for unauthenticated attackers to make web requests to arbitrary internal locations originating from the WordPress server, which can be used to query and modify information from internal services.

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, and no interaction from a victim user.

CWE-918: Server-Side Request Forgery (SSRF)

WordPress 6.9 6.8 – 6.9.1 · 2 branches carries this weakness at wp_remote_post(), and reaching it takes no account at all. Server-side request forgery means the application fetches a URL supplied by the caller, turning the server into a proxy for requests the attacker could not make directly.

The request originates from inside the hosting network, which is how these flaws reach cloud metadata endpoints, internal admin panels and services that trust local traffic. For WordPress 6.9 the fix is 6.8.4: builds 6.8 – 6.9.1 · 2 branches are affected, anything from 6.8.4 onward is not.

Remediation

Update to one of the following versions, or a newer patched version: 6.8.4, 6.9.2

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: updating to 6.8.4 is the step that ends it.

Firewall
Login Security
Alerts

External References

https://www.wordfence.com/threat-intel/vulnerabilities/id/4d4301ca-081b-4fa3-ac4f-aa8f0b37d32c

Related records

Same weakness class

Other vulnerabilities in WordPress 6.9

CVSS Vector

5.8

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeChanged
ConfidentialityNone
IntegrityLow
AvailabilityNone

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