CVE-2021-23209

AMP for WP <= 1.0.77.32 - Authenticated Stored Cross-Site Scripting

2021-12-15 10:11

Strategic Overview

Status: Patched in 1.0.77.33
Affected Plugin: AMP for WP – Accelerated Mobile Pages
Affected Version: <= 1.0.77.32
CVSS: 5.5Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2021-23209

View all AMP for WP – Accelerated Mobile Pages vulnerabilities

At a glance

CVE-2021-23209 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the AMP for WP WordPress plugin, affecting versions <= 1.0.77.32. It carries a CVSS score of 5.5 (reachable over the network; low attack complexity). Exploitation requires an authenticated account. The issue is fixed in version 1.0.77.33; sites on affected versions should update now. Disclosed December 2021.

Vulnerability Overview

Multiple Authenticated (admin user role) Persistent Cross-Site Scripting (XSS) vulnerabilities discovered in AMP for WP – Accelerated Mobile Pages WordPress plugin (versions <= 1.0.77.32).

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 interaction from a victim user.

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

Reaching this weakness in AMP for WP <= 1.0.77.32 takes any authenticated account. 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 AMP for WP the fix is 1.0.77.33: builds <= 1.0.77.32 are affected, anything from 1.0.77.33 onward is not.

Remediation

Update to version 1.0.77.33, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to AMP for WP: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: AMP for WP 1.0.77.33 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-23209 https://www.wordfence.com/threat-intel/vulnerabilities/id/cc6f017d-b0ba-494d-9ad1-8b6cdca48fb1 https://nvd.nist.gov/vuln/detail/CVE-2021-23209

Related records

Same weakness class

Other vulnerabilities in AMP for WP – Accelerated Mobile Pages

CVSS Vector

5.5

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredHigh
User InteractionNone
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone

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