CVE-2026-4519 HIGH

CVE-2026-4519: webbrowser.open() allows leading dashes in URLs

Vendor Python Software Foundation
Product CPython
Published March 20, 2026
Last update June 30, 2026
View on NVD All CVEs

CVSS base score

7.0/10
Attack vector Local
Attack complexity Low
Privileges required None
User interaction —
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

The webbrowser.open() API would accept leading dashes in the URL which could be handled as command line options for certain web browsers. New behavior rejects leading dashes. Users are recommended to sanitize URLs prior to passing to webbrowser.open().

Key dates

02Disclosure timeline

March 20, 2026 CVE published
June 30, 2026 Record updated