CVE-2021-24693: Simple Download Monitor < 3.9.5 - Contributor+ Stored Cross-Site Scripting via File Thumbnail

Severity: critical (CVSS 9.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-11-08 · updated 2026-06-17
Weakness: CWE-79

Description

The Simple Download Monitor WordPress plugin before 3.9.5 does not escape the "File Thumbnail" post meta before outputting it in some pages, which could allow users with a role as low as Contributor to perform Stored Cross-Site Scripting attacks. Given the that XSS is triggered even when the Download is in a review state, contributor could make JavaScript code execute in a context of a reviewer such as admin and make them create a rogue admin account, or install a malicious plugin

Affected products

Simple Download Monitor: before 3.9.5 — fixed in 3.9.5

How to fix

Upgrade to a fixed version: Simple Download Monitor 3.9.5. Check the vendor advisory for mitigations.

References

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