Arbitrary file upload in Bytedesk

CVE-2026-3748

A security flaw has been discovered in Bytedesk up to 1.3.9. This affects the function uploadFile of the file source-code/src/main/java/com/bytedesk/core/upload/UploadRestController.java of the component SVG File Handler. Performing a manipulation results in unrestricted upload. Remote exploitation of the attack is possible. The exploit has been released to the public and may be used for attacks. Upgrading to version 1.4.5.1 is able to mitigate this issue. The patch is named 975e39e4dd527596987559f56c5f9f973f64eff7. Upgrading the affected component is recommended.

EPSS: 0.005 (38.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L.

Affected products

  • Bytedesk
  • N/a Bytedesk — versions 1.3.0, 1.3.1, 1.3.2

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-3748?
CVE-2026-3748 is a medium-severity vulnerability in Bytedesk, classified under Improper Access Control. CVSS score: 6.3/10. Published 2026-03-08.
How severe is CVE-2026-3748?
Medium severity. CVSS v3 base score is 6.3 out of 10.