WP SVG Images <= 3.3 - Authenticated (author+) Stored Cross-Site Scripting via SVG
Strategic Overview
- Status
- Patched in 3.4
- Affected Plugin
- WP SVG Images
- Affected Version
<= 3.3- CVSS
- 6.4Medium
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CVE
CVE-2021-24386
At a glance
CVE-2021-24386 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the WP SVG Images WordPress plugin, affecting versions <= 3.3. It carries a CVSS score of 6.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at author level or above. The issue is fixed in version 3.4; sites on affected versions should update now. Disclosed June 2021, reported by Rasi.
Vulnerability Overview
The WP SVG images WordPress plugin before 3.4 did not sanitise the SVG files uploaded, which could allow low privilege users such as author+ to upload a malicious SVG and then perform XSS attacks by inducing another user to access the file directly. In v3.4, the plugin restricted such upload to editors and admin, with an option to also allow author to do so. The description of the plugin has also been updated with a security warning as upload of such content is intended.
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 WP SVG Images <= 3.3 takes an account at author level or above. 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 WP SVG Images the fix is 3.4: builds <= 3.3 are affected, anything from 3.4 onward is not.
Remediation
Update to version 3.4, or a newer patched version
How does WordSec protect against this?
An attacker needs author access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: WP SVG Images 3.4 closes this, and updating the plugin is the step that ends it.
- Firewall
- Alerts
External References
Related records
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