CVE-2021-32623: apereo opencast XML Entity Expansion

Vulnerability summary

CVE-2021-32623 is a high (CVSS 8.1) XML Entity Expansion vulnerability in apereo opencast. EPSS estimates a 1.25% chance of exploitation in the next 30 days, higher than 69% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 15-06-2021
   PublishedVulnerability first disclosed.
2. 03-08-2024
   Last modifiedVulnerability information updated.

Description

Opencast is a free and open source solution for automated video capture and distribution. Versions of Opencast prior to 9.6 are vulnerable to the billion laughs attack, which allows an attacker to easily execute a (seemingly permanent) denial of service attack, essentially taking down Opencast using a single HTTP request. To exploit this, users need to have ingest privileges, limiting the group of potential attackers The problem has been fixed in Opencast 9.6. There is no known workaround for this issue.

• CWE-776Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')The product uses XML documents and allows their structure to be defined with a Document Type Definition (DTD), but it does not properly control the number of recursive definitions of entities.