Mitgation of CVE-2026-4519 was incomplete. If the URL contained "%action" the mitigation could be bypassed for certain browser types the "webbrowser.open()" API could have commands injected into the underlying shell. See CVE-2026-4519 for details.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
Active
User action required
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 6
https://github.com/python/cpython/commit/c5767a72838a8dda9d6dc5d3558075b055c56b…
cna@python.org
https://github.com/python/cpython/commit/d22922c8a7958353689dc4763dd72da2dea03f…
cna@python.org
https://github.com/python/cpython/commit/f4654824ae0850ac87227fb270f90574779467…
cna@python.org
https://github.com/python/cpython/issues/148169
cna@python.org
https://github.com/python/cpython/pull/148170
cna@python.org
https://mail.python.org/archives/list/security-announce@python.org/thread/JQDUN…
cna@python.org