CVE-2021-43821

CRITICALNVD 9.99.9—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.9 under NVD CVSS v3. EPSS exploit probability: 2.0%, top 22% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this weekElevated
9.9
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 2%CVSS: 9.9Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.9
EG Score
9.9(medium)
EG Risk
65(Track*)
EG Risk 65/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity99% × 45%
Exploitation40% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
78.3%
KEV
Not listed

Published

December 14, 2021

Last Modified

November 21, 2024

Advisory Details (4)

Auto-updated Jul 21, 2026
Patch available. Sources: github_commit, github.
generic

Maven Repository: org.opencastproject » opencast-ingest-service-impl

https://mvnrepository.com/artifact/org.opencastproject/opencast-ingest-service-impl
github Patch Available

Files Accessible to External Parties · Advisory · opencast/opencast · GitHub

https://github.com/opencast/opencast/security/advisories/GHSA-59g4-hpg3-3gcp
github_commit

commit 65c46b9d3e8f (opencast/opencast)

Fix landed in opencast/opencast commit 65c46b9d3e8f — awaiting tagged release

https://github.com/opencast/opencast/commit/65c46b9d3e8f045c544881059923134571897764
generic

opencast/modules/ingest-service-impl/src/main/java/org/opencastproject/ingest/impl/IngestServiceImpl.java at 69952463971cf578363e3b97d8edaf334ff51253 · opencast/opencast · GitHub

https://github.com/opencast/opencast/blob/69952463971cf578363e3b97d8edaf334ff51253/modules/ingest-service-impl/src/main/java/org/opencastproject/ingest/impl/IngestServiceImpl.java#L1587

Affected Packages

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFixed inDependents
org.opencastproject:opencast-ingest-service-impl10.0 ... 9.9 (38 versions)10.6—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 49× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 104 total refreshes for this CVE.

  1. 2026-07-23 02:05 UTCEG score recompute
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Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCJackey0/opencast-CVE-2021-43821-env
    First seen Dec 26, 2021

    opencast cve-2021-43821敏感信息泄露漏洞环境

    Open source ↗

Frequently asked(5)

What is CVE-2021-43821?
CVE-2021-43821 is a critical vulnerability published on December 14, 2021. 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.…
When was CVE-2021-43821 disclosed?
CVE-2021-43821 was first published in the National Vulnerability Database on December 14, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-43821 actively exploited?
CVE-2021-43821 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 78.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-43821?
CVE-2021-43821 has a CVSS v3 base score of 9.9 (NVD).
How do I remediate CVE-2021-43821?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-43821, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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