CVE-2021-43821Public exploitNetwork attack vector

Host file disclosure via unrestricted ingest URI handling

Published Dec 14, 2021 · Updated Aug 4, 2024

Local file disclosure in the Opencast ingest service before 10.6 allows remote authenticated users to expose host files through media packages. The addContentToRepo method accepts a file URI supplied during ingest and calls URL.openStream, copying the referenced local file into managed media. Access to add new media is required, and disclosure is limited to files readable by the Opencast process.

CVSS severity9.9
Critical
EPSS probability1.96%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Local file disclosure in the Opencast ingest service before 10.6 allows remote authenticated users to expose host files through media packages. The addContentToRepo method accepts a file URI supplied during ingest and calls URL.openStream, copying the referenced local file into managed media. Access to add new media is required, and disclosure is limited to files readable by the Opencast process.

The record

CVE
CVE-2021-43821
Published
Dec 14, 2021
Updated
Aug 4, 2024
Vendor
Opencast
Product
Opencast
Classifications
CWE-552, T1005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 10.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Opencast · Opencastversion=< 10.6

Published CVSS scores

7.7NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
4.0NIST NVDAV:N/AC:L/Au:S/C:P/I:N/A:N
9.9GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-552Files or Directories Accessible to External Parties
T1005Data from Local System

Public exploit references

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Technologies

Your stack

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Your stack

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