Medium severity · published Sep 25, 2026
CVE-2026-63208
Zammad: Microsoft Graph error logs expose partially masked OAuth access tokens
5.1
CVSS
0.3%
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 23% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZA
zammad · zammad
< 7.1.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-63208
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-63208
github.com
https://github.com/zammad/zammad/commit/2be46473eee405cc65b86a85d17059802e658532
github.com
https://github.com/zammad/zammad/security/advisories/GHSA-qh8m-g5vr-7272
More from zammad
9.8
CVE-2026-102489
Undisclosed RCE in Zammad v6.3 and higher
7.8
CVE-2026-102490
Local privilege escalation in Zammad v1.5.0 to v7.2.2 installed via DEB or RPM package
9.8
CVE-2022-48021
A vulnerability in Zammad v5.3.0 allows attackers to execute arbitrary code or escalate privileges via a crafted message sent to the server
9.8
CVE-2022-35490
Zammad 5.2.0 is vulnerable to privilege escalation
9.8
CVE-2021-42090
An issue was discovered in Zammad before 4.1.1
