CVE-2021-24854

QR Redirector < 1.6.1 - Stored Cross-Site Scripting

2021-10-18 00:00

Strategic Overview

Status: Patched in 1.6.1
Affected Plugin: QR Redirector
Affected Version: < 1.6.1
CVSS: 5.4Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2021-24854

At a glance

CVE-2021-24854 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the QR Redirector WordPress plugin, affecting versions < 1.6.1. It carries a CVSS score of 5.4 (reachable over the network; low attack complexity). The issue is fixed in version 1.6.1; sites on affected versions should update now. Disclosed October 2021, reported by apple502j.

Vulnerability Overview

The QR Redirector WordPress plugin before 1.6.1 does not sanitise and escape some of the QR Redirect fields, which could allow users with a role as low as Contributor perform Stored Cross-Site Scripting attacks.

Technical Analysis

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

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

Reaching this weakness in QR Redirector < 1.6.1 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 QR Redirector the fix is 1.6.1: builds < 1.6.1 are affected, anything from 1.6.1 onward is not.

Remediation

Update to version 1.6.1, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to QR Redirector: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: QR Redirector 1.6.1 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24854 https://www.wordfence.com/threat-intel/vulnerabilities/id/bc2ee795-39e5-48c2-ac2a-cfc520bdd857 https://nvd.nist.gov/vuln/detail/CVE-2021-24854

Related records

Other vulnerabilities in QR Redirector

CVSS Vector

5.4

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

Base

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

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