CVE-2021-24977

Use Any Font <= 6.2.0 - Unauthenticated Arbitrary CSS Appending

2022-01-31 00:00

Strategic Overview

Status: Patched in 6.2.1
Affected Plugin: Use Any Font | Custom Font Uploader
Affected Version: < 6.2.1
CVSS: 6.1Medium
Weakness type: CWE-862 · Missing Authorization
CVE: CVE-2021-24977

View all Use Any Font | Custom Font Uploader vulnerabilities

At a glance

CVE-2021-24977 is a medium-severity Missing Authorization vulnerability in the Use Any Font WordPress plugin, affecting versions < 6.2.1. 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 6.2.1; sites on affected versions should update now. Disclosed January 2022, reported by Krzysztof Zając.

Vulnerability Overview

The Use Any Font | Custom Font Uploader WordPress plugin before 6.2.1 does not have any authorisation checks when assigning a font, allowing unauthenticated users to send arbitrary CSS which will then be processed by the frontend for all users. Due to the lack of sanitisation and escaping in the backend, it could also lead to Stored XSS issues

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-862: Missing Authorization

Reaching this weakness in Use Any Font < 6.2.1 takes no account at all. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.

Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For Use Any Font the fix is 6.2.1: builds < 6.2.1 are affected, anything from 6.2.1 onward is not.

Remediation

Update to version 6.2.1, or a newer patched version

How does WordSec protect against this?

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: Use Any Font 6.2.1 closes this, and updating the plugin is the step that ends it.

Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24977 https://www.wordfence.com/threat-intel/vulnerabilities/id/cb6de4da-0d60-4332-be25-5521e430a4fa https://nvd.nist.gov/vuln/detail/CVE-2021-24977

Related records

Other vulnerabilities in Use Any Font | Custom Font Uploader

CVSS Vector

6.1

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone

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