Inappropriate Encoding for Output Context in Zammad - CVE-2026-84463
Published: October 3, 2026
Vulnerability identifier: #VU153220
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-84463
CWE-ID: CWE-838
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to switch another user's session to an attacker-chosen account.
The vulnerability exists due to inappropriate encoding for output context in the Knowledge Base video widget iframe attribute when rendering a published Knowledge Base answer containing a crafted video widget value. A remote user can embed a video widget with a specially crafted value to switch another user's session to an attacker-chosen account.
The viewer must have permission to switch between user sessions, and opening the published answer is sufficient to trigger the request.
Affected software
Zammad
How to mitigate CVE-2026-84463
Install security update from vendor's website.
Zammad - update to 7.1.2