CVE-2026-4786

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.
Command Injection
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
PSFCNA
7 HIGH
LOCAL
LOW
NONE
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
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
pythoncpython
𝑥
< 3.15.0
CNA
Common Weakness Enumeration
References
https://github.com/python/cpython/issues/148169
https://github.com/python/cpython/pull/148170
https://mail.python.org/archives/list/security-announce@python.org/thread/JQDUNJVB4AQNTJECSUKOBDU3XCJIPSE5/