CVE-2023-5561

WordPress Core 4.7.0 - 6.3.1 - Sensitive Information Exposure via User Search REST Endpoint

2023-10-12 00:00

Strategic Overview

Status: Patched in 4.7.27
Affected Core: WordPress 6.3
Affected Version: 4.7 – 6.3.1 · 17 branches
CVSS: 5.3Medium
Weakness type: CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor
CVE: CVE-2023-5561

At a glance

CVE-2023-5561 is a medium-severity Exposure of Sensitive Information to an Unauthorized Actor vulnerability in the WordPress 6.3 WordPress release line, affecting 4.7 – 6.3.1 · 17 branches. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 4.7.27; sites on affected versions should update now. Disclosed October 2023, reported by Marc-Alexandre Montpas.

Vulnerability Overview

WordPress Core is vulnerable to Sensitive Information Exposure in versions between 4.7.0 and 6.3.1 via the User REST endpoint. While the search results do not display user email addresses unless the requesting user has the 'list_users' capability, the search is applied to the user_email column. This can allow unauthenticated attackers to brute force or verify the email addresses of users with published posts or pages on the site.

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-200: Exposure of Sensitive Information to an Unauthorized Actor

WordPress 6.3 4.7 – 6.3.1 · 17 branches carries this weakness at list_users, and reaching it takes a caller who can reach the endpoint. Sensitive information exposure means data the application intended to keep internal is returned to a caller who should not be able to see it.

The disclosed data — credentials, tokens, customer records or internal paths — is usually worth more as material for a follow-up attack than as an end in itself. For WordPress 6.3 the fix is 4.7.27: builds 4.7 – 6.3.1 · 17 branches are affected, anything from 4.7.27 onward is not.

Remediation

Update to one of the following versions, or a newer patched version: 4.7.27, 4.8.23, 4.9.24, 5.0.20, 5.1.17, 5.2.19, 5.3.16, 5.4.14, 5.5.13, 5.6.12, 5.7.10, 5.8.8, 5.9.8, 6.0.6, 6.1.4, 6.2.3, 6.3.2

How does WordSec protect against this?

The fix is the thing that ends this: updating to 4.7.27 is the step that ends it.

Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2023-5561 https://www.wordfence.com/threat-intel/vulnerabilities/id/38b63167-e1a6-4279-97cf-900df0651f20 https://nvd.nist.gov/vuln/detail/CVE-2023-5561

Related records

Same weakness class

Other vulnerabilities in WordPress 6.3

CVSS Vector

5.3

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityLow
IntegrityNone
AvailabilityNone

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