CVE-2020-23762

Larsens Calender <= 1.2 - Authenticated Stored Cross-Site Scripting

2021-04-09 00:00
Th3 Hidd3n 0n3

Strategic Overview

Status
Unpatched
Affected Plugin
Larsens Calender
Affected Version
<= 1.2
CVSS
6.4Medium
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2020-23762
View all Larsens Calender vulnerabilities

At a glance

CVE-2020-23762 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Larsens Calender WordPress plugin, affecting versions <= 1.2. It carries a CVSS score of 6.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account. No fixed release has been reported yet; treat installations running this software as exposed. Disclosed April 2021, reported by Th3 Hidd3n 0n3.

Vulnerability Overview

Cross Site Scripting (XSS) vulnerability in the Larsens Calender plugin Version <= 1.2 for WordPress allows remote attackers to execute arbitrary web script via the "tite" column on the "Eintrage hinzufugen" tab.

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')

Larsens Calender <= 1.2 carries this weakness at tite, and reaching it 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. No fixed build of this plugin is recorded for Larsens Calender yet, so installs running <= 1.2 stay exposed until the vendor ships one.

Remediation

No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.

How does WordSec protect against this?

The attempt arrives as an ordinary request to Larsens Calender: WordSec's web application firewall inspects request payloads before WordPress loads them. No patched version is recorded yet, which is the case where a filtering layer matters most, because there is nothing to update to.

  • Firewall
  • Alerts

External References

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C