CVE-2026-50873 | BDVDB-2026-340516 Detail

Description#

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.

Impact#

Per CVSS v3.1: confidentiality impact high, integrity impact high, availability impact high. Attack vector: network.

Weaknesses#

CWE-434 Unrestricted Upload of File with Dangerous Type

References#

https://gist.github.com/pyuysig/ab0af5b10877fb906941e05a69b202a7

Exploit#

No public exploit known

History#

Version 12026-06-15Record published in the CVE List.
Version 22026-06-16Most recent update recorded in the CVE List.

Published

Published: 2026-06-15
Last modified: 2026-06-16

Vendor information

Vendor: Not stated
Product: Not stated

Score

9.8 Critical

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 38.6.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Unrestricted File Upload

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

No version data in the source record.

Scoring System

CVSS v4.0

Not available

CVSS v3.1

9.8 Critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	None
User Interaction	None
Scope	Unchanged
Confidentiality	High
Integrity	High
Availability	High

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).