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CVE-2026-4519

webbrowser.open() allows leading dashes in URLs

Published: Mar 20, 2026Updated: Apr 16, 2026 Sources: CVE List NVD BDUCWE-20
NVD MITRE
3.3CVSSLOW
EPSS Score
0.2%
Top 88.1%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

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 Vector Breakdown

AV:LAC:LPR:NUI:RS:UC:NI:LA:N
Exploitability
AV:LAttack Vector
Local
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:LIntegrity
Low
A:NAvailability
None
Open in CVSS calculator →

Weaknesses

CWE-20

Affected Products

CPythonPython Software FoundationOSS Libraries
pythonpythonOSS Libraries
Red Hat Enterprise LinuxRed Hat Inc.
On-premOS
Operating Systems / linux-distro
Debian GNU/LinuxСообщество свободного программного обеспечения
On-premOS
Operating Systems / linux-distro
РЕД ОСООО «Ред Софт»
On-premOS
Operating Systems / linux-distro
python software foundationoss-projectUSOSS Librariesaka python software foundation, psf
pythonoss-projectUSOSS Libraries
red hat inc.commercialUSOperating Systemsaka red hat
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf
ооо «ред софт»commercialRUOperating Systemsaka red soft
and 6 more affected products View all →

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Initial Access
View detailed technique mapping

References

https://github.com/python/cpython/pull/143931
github.com
https://github.com/python/cpython/issues/143930
github.com
https://mail.python.org/archives/list/security-announce@python.org/thread/AY5NDSS433JK56Q7Q5IS7B37QFZVVOUS/
mail.python.org
and 33 more references View all →

Timeline

Published
Mar 20, 2026
Last Updated
Apr 16, 2026

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