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Medium

Security advisory

Type: advisorySources: OSVCVE: 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.

Products
Not specified
Affected versions
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Fixed versions
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CVEs
CVE-2021-32623
Confirmed fixed CVEs
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Updated in this feed
31 Oct 2026, 11:46 UTC · Revision 1

Source evidence

CVE-2021-32623

core-osv · Original source

Published 16 Jun 2021, 00:15 UTC

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"
}