CVE-2026-4786

HIGH

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

Title source: cna
STIX 2.1

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.

References (8)

Core 8
Core References
Issue Tracking issue-tracking
https://github.com/python/cpython/issues/148169

Scores

CVSS v4 7.0
EPSS 0.0021
EPSS Percentile 11.0%
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

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-77
Status published
Products (4)
Python Software Foundation/CPython < 3.13.14
Python Software Foundation/CPython < 3.15.0
Python Software Foundation/CPython 3.14.0a1 - 3.14.5rc1
Python Software Foundation/CPython 3.15.0a1 - 3.15.0b1
Published Apr 13, 2026
Tracked Since Apr 14, 2026