Opencast up to 19.6/20.1 Session mh_default_org.xml jsessionid session fixiation

Summaryinfo

A vulnerability was found in Opencast up to 19.6/20.1. It has been rated as critical. Affected by this vulnerability is an unknown functionality of the file etc/security/mh_default_org.xml of the component Session Handler. This manipulation of the argument jsessionid causes session fixiation. This vulnerability appears as CVE-2026-77614. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Opencast up to 19.6/20.1. It has been declared as critical. Affected by this vulnerability is an unknown function of the file etc/security/mh_default_org.xml of the component Session Handler. The manipulation of the argument jsessionid with an unknown input leads to a session fixiation vulnerability. The CWE definition for the vulnerability is CWE-384. Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Opencast is a free, open-source platform to support the management of educational audio and video content. Prior to versions 19.7 and 20.2, the default security configuration in etc/security/mh_default_org.xml accepts a client-selected JSESSIONID from the ;jsessionid= URL path parameter and does not replace it when the victim logs in. An unauthenticated attacker can send a crafted link to a victim whose browser has no active Opencast session cookie, wait for the victim to authenticate, and then reuse the known identifier as the victim's authenticated session. This can expose the victim's data and actions and can produce full administrative account takeover when the victim is an administrator. This issue is fixed in versions 19.7 and 20.2.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-77614 since 08/20/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

By approaching the search of inurl:etc/security/mh_default_org.xml it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 19.7 or 20.2 eliminates this vulnerability.

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Productinfo

Name

• Opencast

Version

• 19.0
• 19.1
• 19.2
• 19.3
• 19.4
• 19.5
• 19.6
• 20.0
• 20.1

Website

• Product: https://github.com/opencast/opencast/

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