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CVE-2026-4519

webbrowser.open() allows leading dashes in URLs

Published: 3/20/2026 Last updated: 4/13/2026 Reserved: 3/20/2026

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().

CNA assigner: PSF (28c92f92-d60d-412d-b760-e73465c3df22) Requested by: n/a

Metrics

Version Score Severity Vector String
4.0 7 High 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

Opam packages affected (7)

conf-python-2-7 conf-python-2-7-dev conf-python-3 conf-python-3-7 conf-python-3-dev py termbox

Products affected (2)

Product Vendor Version
CPython Python Software Foundation n/a
CPython Python Software Foundation n/a

References (32)

Credits (6)