PT-2026-49314 · Flatnotes · Flatnotes

Pyuysig · CVE-2026-50873 · Published 2026-06-15 · Updated 2026-06-16

Positive Technologies (AI Summary)

CVSS v3.1

9.8

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions flatnotes version 5.5.4

Description An arbitrary file upload issue exists in the attachment handling component. This allows attackers to execute arbitrary code by uploading a specially crafted HTML or SVG file.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Unrestricted File Upload

Weakness Enumeration

CWE-434

Related Identifiers

CVE-2026-50873

Affected Products

Flatnotes

References · 3

• 🔥 https://gist.github.com/pyuysig/ab0af5b10877fb906941e05a69b202a7 · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-50873 · Security Note
• https://t.me/cveNotify/168572 · Telegram Post