Zammad: Microsoft Graph error logs expose partially masked OAuth access tokens
Historical advisory recorded 23 Oct 2026 15:48:27 UTC. Read the latest advisory.
cve-program · CVE-2026-63208
PublishedZammad 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.
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cve-program · CVE-2026-63208
PublishedZammad: Microsoft Graph error logs expose partially masked OAuth access tokens
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.
- Source published
- 25 Sep 2026 18:23:47 UTC
- Source modified
- 25 Sep 2026 18:42:12 UTC
- Saved here
- 23 Oct 2026 15:48:27 UTC
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CVSS 4.0 · 5.1 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