Arbitrary file upload in N/a

CVE-2026-50873

An arbitrary file upload vulnerability in the attachment handling component of flatnotes v5.5.4 allows attackers to execute arbitrary code via uploading a crafted HTML or SVG file.

Vulnerability class: Unrestricted File Upload

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (49.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 49.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-50873: held from 0.004 to 0.006.

EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-50873?
CVE-2026-50873 is a critical-severity vulnerability in N/a, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 9.8/10. Published 2026-06-15.
How severe is CVE-2026-50873?
Critical severity. CVSS v3 base score is 9.8 out of 10.