CVE-2021-43821

What it is

Opencast is an Open Source Lecture Capture & Video Management for Education. Opencast before version 9.10 or 10.6 allows references to local file URLs in ingested media packages, allowing attackers to include local files from Opencast's host machines and making them available via the web interface. Before Opencast 9.10 and 10.6, Opencast would open and include local files during ingests. Attackers could exploit this to include most local files the process has read access to, extracting secrets from the host machine. An attacker would need to have the privileges required to add new media to exploit this. But these are often widely given. The issue has been fixed in Opencast 10.6 and 11.0. You can mitigate this issue by narrowing down the read access Opencast has to files on the file system using UNIX permissions or mandatory access control systems like SELinux. This cannot prevent access to files Opencast needs to read though and we highly recommend updating.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data exposure, data tampering, service disruption.

Exploit odds

2.0% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-12-14 20:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 04:11 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 2.0% in the next 30 days (EPSS).
• Severity: 9.9 CRITICAL (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-12-14 20:15 UTC

Last modified

2026-06-17 04:11 UTC

Exploit probability

2.0% · EPSS, next 30 days

Weakness

CWE-552

Record status

Modified

Affected

• Apereo Opencast < 10.6

Attack profile CVSS 3.1 · 9.9

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-43821.md and follow it. Check whether this project is affected by CVE-2021-43821. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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