CVE-2026-4786

high

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

https://mail.python.org/archives/list/[email protected]/thread/JQDUNJVB4AQNTJECSUKOBDU3XCJIPSE5/

https://github.com/python/cpython/pull/148170

https://github.com/python/cpython/issues/148169

https://github.com/python/cpython/commit/f4654824ae0850ac87227fb270f9057477946769

https://github.com/python/cpython/commit/d22922c8a7958353689dc4763dd72da2dea03fff

https://github.com/python/cpython/commit/c5767a72838a8dda9d6dc5d3558075b055c56bca

Details

Source: Mitre, NVD

Published: 2026-04-13

Updated: 2026-04-14

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Severity: High

CVSS v3

Base Score: 9.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

CVSS v4

Base Score: 7

Vector: 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