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Fencer Intel
medium 5.1

CVE-2026-63208 json

Zammad: Microsoft Graph error logs expose partially masked OAuth access tokens

published 3mo ago modified last mo. also EUVD-2026-87271 , GHSA-qh8m-g5vr-7272

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository zammad/zammad. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
5.1
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

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.

Patch / fix

  • zammad zammad 7.1.2

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 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
CNA 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • zammad zammad

Classification

Weakness
  • CWE-116 Improper Encoding or Escaping of Output
  • CWE-532 Insertion of Sensitive Information into Log File

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of zammad/zammad published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.