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.

Score

CVSS 3.1 7.1 High

Status

Awaiting Analysis - cna@python.org

Published

2026-04-13

Last modified

2026-10-26

Weaknesses

CWE-77, CWE-88

Affected products

• Cpython (Python Software Foundation)
• Ai Inference Server (Redhat)
• Enterprise Linux (Redhat)
• Enterprise Linux Ai (Redhat)
• Enterprise Linux Eus (Redhat)
• Hummingbird (Redhat)
• Rhel Aus (Redhat)
• Rhel E4s (Redhat)
• Rhel Els (Redhat)
• Rhel Eus (Redhat)
• Rhel Eus Long Life (Redhat)
• Rhel Tus (Redhat)
• Rhosemc (Redhat)
• Rhui (Redhat)

References

• https://github.com/python/cpython/pull/148170
• https://github.com/python/cpython/issues/148169
• https://mail.python.org/archives/list/security-announce@python.org/thread/JQDUNJVB4AQNTJECSUKOBDU3XCJIPSE5/
• https://github.com/python/cpython/commit/c5767a72838a8dda9d6dc5d3558075b055c56bca
• https://github.com/python/cpython/commit/d22922c8a7958353689dc4763dd72da2dea03fff
• https://github.com/python/cpython/commit/f4654824ae0850ac87227fb270f9057477946769
• https://github.com/python/cpython/commit/28b4ad38067bbdad34edfcd03ad2de5f06387e53
• https://github.com/python/cpython/commit/d6d68494be70bdbda20f89f83801ba52ec37daa4
• https://github.com/python/cpython/commit/a4d3edf3a6ecfde504d02126410d2a65a859b744
• https://access.redhat.com/security/cve/CVE-2026-4786
• https://bugzilla.redhat.com/show_bug.cgi?id=2458049
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4786.json
• https://access.redhat.com/errata/RHSA-2026:22144
• https://access.redhat.com/errata/RHSA-2026:19589
• https://access.redhat.com/errata/RHSA-2026:35838
• https://access.redhat.com/errata/RHSA-2026:13812
• https://access.redhat.com/errata/RHSA-2026:16699
• https://access.redhat.com/errata/RHSA-2026:10711
• https://access.redhat.com/errata/RHSA-2026:19064
• https://access.redhat.com/errata/RHSA-2026:19019
• https://access.redhat.com/errata/RHSA-2026:28581
• https://access.redhat.com/errata/RHSA-2026:11077
• https://access.redhat.com/errata/RHSA-2026:11062
• https://access.redhat.com/errata/RHSA-2026:10950
• https://access.redhat.com/errata/RHSA-2026:19590
• https://access.redhat.com/errata/RHSA-2026:17619
• https://access.redhat.com/errata/RHSA-2026:19549
• https://access.redhat.com/errata/RHSA-2026:26187
• https://access.redhat.com/errata/RHSA-2026:19571
• https://access.redhat.com/errata/RHSA-2026:19570