SB2026100309 - Multiple vulnerabilities in Zammad

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Main Vulnerability Database SB2026100309

SB2026100309 - Multiple vulnerabilities in Zammad

Published: October 3, 2026

Security Bulletin ID SB2026100309
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 3
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 33% Low 67%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 3 vulnerabilities.


1) Cross-site scripting (CVE-ID: CVE-2026-102345)

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSSv4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N]


The vulnerability allows a remote user to execute arbitrary script.

The vulnerability exists due to improper output encoding in ticket article rendering in the new Vue-based interface when rendering crafted ticket article content. A remote user can submit crafted ticket article content to execute arbitrary script.

User interaction is required to view the ticket.


2) Improper Certificate Validation (CVE-ID: CVE-2026-84465)

CWE-ID: CWE-295 - Improper Certificate Validation

CVSSv4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to impersonate a trusted sender.

The vulnerability exists due to improper certificate validation in S/MIME signature verification when checking incoming S/MIME-signed emails. A remote attacker can create a certificate using the name of a previously trusted sender and send a forged signed email to impersonate a trusted sender.

User interaction is required.


3) Inappropriate Encoding for Output Context (CVE-ID: CVE-2026-84463)

CWE-ID: CWE-838 - Inappropriate Encoding for Output Context

CVSSv4: 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]


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.


Remediation

Install update from vendor's website.

References