Vulnerability · Published Sep 25, 2026 · Assigned by GitHub_M
CVE-2026-63208Zammad: Microsoft Graph error logs expose partially masked OAuth access tokens
Medium 5.1
In plain English
A medium-severity sensitive data in logs in zammad from zammad. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities).
Official description
Zammad is a web based open source helpdesk/customer support system. Prior to 7.1.2, when a Microsoft Graph request fails, Zammad logs the error including the authentication token used to access the mailbox. The system attempts to hide this token in the log, but the masking is incomplete: for the token format Microsoft uses (JWT), only the first part is hidden, while the remaining parts remain readable in plain text. A Zammad admin with Microsoft Graph channel access can view these logs and see the partial token, which may reveal sensitive claims such as the account scope, tenant, or timing, and could assist in reconstructing the full token while it is still valid. This issue is fixed in version 7.1.2.
Affected products (as reported)
Weakness: CWE-116, CWE-532 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N