CVE-2021-43807Public exploitNetwork attack vector

State changes via spoofed HTTP method parameter

Published Dec 14, 2021 · Updated Aug 4, 2024

HTTP method spoofing in Opencast before 9.10 allows remote attackers to change server state through cross-site request forgery. The _method URL parameter overrides the actual HTTP method, converting GET or form requests into PUT or DELETE operations that evade method restrictions. Exploitation requires an authenticated user, such as an administrator, to follow a crafted link or submit a form; permitted state changes depend on the user's privileges.

CVSS severity7.5
High
EPSS probability1.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTTP method spoofing in Opencast before 9.10 allows remote attackers to change server state through cross-site request forgery. The _method URL parameter overrides the actual HTTP method, converting GET or form requests into PUT or DELETE operations that evade method restrictions. Exploitation requires an authenticated user, such as an administrator, to follow a crafted link or submit a form; permitted state changes depend on the user's privileges.

The record

CVE
CVE-2021-43807
Published
Dec 14, 2021
Updated
Aug 4, 2024
Vendor
Opencast
Product
Opencast
Classifications
CWE-290, T1189
Attack vector
network
Privileges
unauthenticated

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=< 9.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Opencast · Opencastversion=< 9.10

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
7.5GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

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.

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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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing
T1189Drive-by Compromise

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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