Security advisory
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-32623
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 11:46 UTC · Revision 1
Source evidence
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.
osv:CVE-2021-32623
Complete source record
{
"id": "1e9162a43019552606414589fd45c70fc10a6a41ac578abe2489e53ac51fe2a3",
"url": "https://osv.dev/vulnerability/CVE-2021-32623",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-32623",
"summary": "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.",
"evidence": "osv:CVE-2021-32623",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2021-32623",
"aliases": [
"CVE-2021-32623",
"GHSA-9gwx-9cwp-5c2m"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/opencast/opencast",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "17f54e0f7060759ab7e9a68e18c7be9941774b4d"
},
{
"fixed": "8ae27da5a6f658011a5741b3210e715b0dc6213e"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:apereo:opencast:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "9.6"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "8ae27da5a6f658011a5741b3210e715b0dc6213e"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-32623.json"
}
}
],
"modified": "2026-10-20T10:54:41.754349022Z",
"provider": "osv",
"references": [
"https://github.com/opencast/opencast/commit/8ae27da5a6f658011a5741b3210e715b0dc6213e",
"https://github.com/opencast/opencast/security/advisories/GHSA-9gwx-9cwp-5c2m"
],
"provider_metadata": {}
},
"related_cves": [
{
"value": "CVE-2021-32623",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 385913,
"published_at": "2021-06-16T00:15:07.717+00:00"
}