CVE-2021-43807: HTTP Method Spoofing in Opencast

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-12-14 · updated 2026-06-17
Weakness: CWE-290

Description

Opencast is an Open Source Lecture Capture & Video Management for Education. Opencast versions prior to 9.10 allow HTTP method spoofing, allowing to change the assumed HTTP method via URL parameter. This allows attackers to turn HTTP GET requests into PUT requests or an HTTP form to send DELETE requests. This bypasses restrictions otherwise put on these types of requests and aids in cross-site request forgery (CSRF) attacks, which would otherwise not be possible. The vulnerability allows attackers to craft links or forms which may change the server state. This issue is fixed in Opencast 9.10 and 10.0. You can mitigate the problem by setting the `SameSite=Strict` attribute for your cookies. If this is a viable option for you depends on your integrations. We strongly recommend updating in any case.

Affected products

opencast: before 9.10 — fixed in 9.10

How to fix

Upgrade to a fixed version: opencast 9.10. Check the vendor advisory for mitigations.

References

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