CVE-2026-63208 Zammad: Microsoft Graph error logs expose partially masked OAuth access tokens
Zammad admins can view partially masked OAuth tokens in error logs, potentially exposing sensitive claims and aiding token reconstruction.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-63208?
CVE-2026-63208 is a medium-severity vulnerability in zammad, published on 25 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
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.
Which versions are affected by CVE-2026-63208?
How do I fix CVE-2026-63208?
No fix has been published for CVE-2026-63208 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-63208 being exploited?
There is no known exploitation of CVE-2026-63208 in the wild and no public exploit code.
Sources
Also known as GHSA-qh8m-g5vr-7272.