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CVE-2026-4786

Incomplete mitigation of CVE-2026-4519, %action expansion for command injection to webbrowser.open()

Published: Apr 13, 2026Updated: Jun 30, 2026 Sources: CVE List NVDCWE-77
7.1HIGH
NVD MITRE
EPSS Score
0.3%
Top 79.3%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:RS:UC:HI:HA:L
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:LAvailability
Low
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Weaknesses

CWE-77CWE-88

Affected Products

Python Software Foundation
oss-project·USaka psf
CPython
OSS Libraries

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
Scannable·OpenVAS
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Execution
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References

https://github.com/python/cpython/commit/28b4ad38067bbdad34edfcd03ad2de5f06387e53
github.com
https://github.com/python/cpython/commit/c5767a72838a8dda9d6dc5d3558075b055c56bca
github.com
https://github.com/python/cpython/commit/d22922c8a7958353689dc4763dd72da2dea03fff
github.com
and 53 more references View all →
News mentions
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