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Fencer Intel
high 8.7

CVE-2026-68899 json

Wekan: File Upload MIME Type Validation Bypass — Stored XSS via Missing System Binary Fallback

published 3mo ago modified 16d ago also EUVD-2026-62706 , GHSA-jhph-whx8-wq6p

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository wekan/wekan. 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
8.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

Wekan is open source kanban built with Meteor. Prior to 9.90, isFileValid() in models/fileValidation.js used the Unix file command for content-based MIME detection, but detectMimeFromFile() silently returned undefined when that binary was unavailable and the validation fell back to the attacker-controlled fileObj.type supplied through server/routes/attachmentApi.js. On deployments with WITH_API=true and no file binary, an authenticated board member could label HTML containing JavaScript as image/png, bypass the dangerous MIME check, and store active content under the Wekan origin for execution when another user opened it. Version 9.90 adds looksLikeDangerousMarkup() to inspect file bytes and force dangerous-content scanning when MIME detection is unavailable. This issue is fixed in version 9.90.

Patch / fix

  • wekan_project wekan 9.90

Is CVE-2026-68899 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 8.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Affected products

  • wekan wekan

Classification

Weakness
  • CWE-434 Unrestricted Upload of File with Dangerous Type

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 wekan/wekan 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.