CVE-2026-4519highCWE-20CWE-88

CVE-2026-4519: high-severity vulnerability in Python Software Foundation CPython

webbrowser.open() allows leading dashes in URLs

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21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7epss 0.3%
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().
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
Affected products
Python Software Foundation · CPython
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