---
id: CVE-2026-4786
title: "Mitgation of\_CVE-2026-4519 was incomplete"
summary: "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 fo…"
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L'
cwe:
  - CWE-77
  - CWE-88
published: '2026-04-13'
updated: '2026-07-06'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-4786'
references:
  - url: >-
      https://github.com/python/cpython/commit/28b4ad38067bbdad34edfcd03ad2de5f06387e53
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/c5767a72838a8dda9d6dc5d3558075b055c56bca
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/d22922c8a7958353689dc4763dd72da2dea03fff
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/d6d68494be70bdbda20f89f83801ba52ec37daa4
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/f4654824ae0850ac87227fb270f9057477946769
    label: cna@python.org
  - url: 'https://github.com/python/cpython/issues/148169'
    label: cna@python.org
  - url: 'https://github.com/python/cpython/pull/148170'
    label: cna@python.org
  - url: >-
      https://mail.python.org/archives/list/security-announce@python.org/thread/JQDUNJVB4AQNTJECSUKOBDU3XCJIPSE5/
    label: cna@python.org
  - url: 'https://access.redhat.com/errata/RHSA-2026:10117'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:10140'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:10141'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:10711'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:10745'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:10774'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:10949'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:10950'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:11062'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:11077'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:11768'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:13692'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:13812'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:14652'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:14653'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:14656'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:16699'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:17525'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:17619'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19019'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19064'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19175'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19176'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19177'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19216'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19549'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19570'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19571'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19576'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19589'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19590'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:21275'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:21682'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:22144'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:25096'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:26187'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:28247'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:28581'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:30078'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:30087'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:30088'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:30089'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:35838'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:8822'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:8824'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:9228'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-4786'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2458049'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4786.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-4786'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-4786'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.0029
epssPercentile: 0.21439
ingestedAt: '2026-07-06T17:44:51.141Z'
vendor: Red Hat
product: Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)
affected:
  - enterprise_linux 8
  - enterprise_linux_server_extension_v_6_els_extension
  - enterprise_linux_server_optional_extension_v_6_els_extension
  - enterprise_linux_server_v_7_els
  - enterprise_linux_server_optional_v_7_els
  - middleware_containers_for_openshift
  - enterprise_linux_appstream_eus_v_10_0
  - enterprise_linux_appstream_v_10
  - enterprise_linux_appstream_v_8
  - enterprise_linux_appstream_aus_v_8_4
  - enterprise_linux_appstream_eus_extension_v_8_4
  - enterprise_linux_appstream_aus_v_8_6
  - enterprise_linux_appstream_e4s_v_8_6
  - enterprise_linux_appstream_tus_v_8_6
  - enterprise_linux_appstream_e4s_v_8_8
  - enterprise_linux_appstream_tus_v_8_8
  - enterprise_linux_appstream_e4s_v_9_0
  - enterprise_linux_appstream_e4s_v_9_2
  - enterprise_linux_appstream_eus_v_9_4
  - enterprise_linux_appstream_eus_v_9_6
  - enterprise_linux_appstream_v_9
  - enterprise_linux_baseos_eus_v_10_0
  - enterprise_linux_baseos_v_10
  - enterprise_linux_baseos_v_8
  - enterprise_linux_baseos_aus_v_8_4
  - enterprise_linux_baseos_eus_extension_v_8_4
  - enterprise_linux_baseos_aus_v_8_6
  - enterprise_linux_baseos_e4s_v_8_6
  - enterprise_linux_baseos_tus_v_8_6
  - enterprise_linux_baseos_e4s_v_8_8
  - enterprise_linux_baseos_tus_v_8_8
  - enterprise_linux_baseos_e4s_v_9_0
  - enterprise_linux_baseos_e4s_v_9_2
  - enterprise_linux_baseos_eus_v_9_4
  - enterprise_linux_baseos_eus_v_9_6
  - enterprise_linux_baseos_v_9
  - enterprise_linux_codeready_linux_builder_eus_v_10_0
  - enterprise_linux_codeready_linux_builder_v_10
  - enterprise_linux_crb_v_8
  - codeready_linux_builder_eus_v_9_4
patched:
  - enterprise_linux_server_extension_v_6_els_extension
  - enterprise_linux_server_optional_extension_v_6_els_extension
  - enterprise_linux_server_v_7_els
  - enterprise_linux_server_optional_v_7_els
  - middleware_containers_for_openshift
  - enterprise_linux_appstream_eus_v_10_0
  - enterprise_linux_appstream_v_10
  - enterprise_linux_appstream_v_8
  - enterprise_linux_appstream_aus_v_8_4
  - enterprise_linux_appstream_eus_extension_v_8_4
  - enterprise_linux_appstream_aus_v_8_6
  - enterprise_linux_appstream_e4s_v_8_6
  - enterprise_linux_appstream_tus_v_8_6
  - enterprise_linux_appstream_e4s_v_8_8
  - enterprise_linux_appstream_tus_v_8_8
  - enterprise_linux_appstream_e4s_v_9_0
  - enterprise_linux_appstream_e4s_v_9_2
  - enterprise_linux_appstream_eus_v_9_4
  - enterprise_linux_appstream_eus_v_9_6
  - enterprise_linux_appstream_v_9
  - enterprise_linux_baseos_eus_v_10_0
  - enterprise_linux_baseos_v_10
  - enterprise_linux_baseos_v_8
  - enterprise_linux_baseos_aus_v_8_4
  - enterprise_linux_baseos_eus_extension_v_8_4
  - enterprise_linux_baseos_aus_v_8_6
  - enterprise_linux_baseos_e4s_v_8_6
  - enterprise_linux_baseos_tus_v_8_6
  - enterprise_linux_baseos_e4s_v_8_8
  - enterprise_linux_baseos_tus_v_8_8
  - enterprise_linux_baseos_e4s_v_9_0
  - enterprise_linux_baseos_e4s_v_9_2
  - enterprise_linux_baseos_eus_v_9_4
  - enterprise_linux_baseos_eus_v_9_6
  - enterprise_linux_baseos_v_9
  - enterprise_linux_codeready_linux_builder_eus_v_10_0
  - enterprise_linux_codeready_linux_builder_v_10
  - enterprise_linux_crb_v_8
  - codeready_linux_builder_eus_v_9_4
  - codeready_linux_builder_eus_v_9_6
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:22144** · Red Hat · fixed in: Red Hat Enterprise Linux Server -EXTENSION(v. 6 ELS-EXTENSION), Red Hat Enterprise Linux Server Optional -EXTENSION (v. 6 ELS -EXTENSION) · released 2026-06-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:22144)
- **RHSA-2026:19589** · Red Hat · fixed in: Red Hat Enterprise Linux Server (v. 7 ELS), Red Hat Enterprise Linux Server Optional (v. 7 ELS) · released 2026-05-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:19589)
- **RHSA-2026:35838** · Red Hat · fixed in: Red Hat Enterprise Linux Server (v. 7 ELS), Red Hat Enterprise Linux Server Optional (v. 7 ELS) · released 2026-07-06 · [advisory](https://access.redhat.com/errata/RHSA-2026:35838)
- **RHSA-2026:13812** · Red Hat · fixed in: Middleware Containers for OpenShift · released 2026-05-05 · [advisory](https://access.redhat.com/errata/RHSA-2026:13812)
- **RHSA-2026:16699** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) · released 2026-05-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:16699)
- **RHSA-2026:10711** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · released 2026-04-27 · [advisory](https://access.redhat.com/errata/RHSA-2026:10711)
- **RHSA-2026:19064** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19064)
- **RHSA-2026:19019** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19019)
- **RHSA-2026:28581** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · released 2026-06-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:28581)
- **RHSA-2026:11077** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux BaseOS (v. 8) · released 2026-04-27 · [advisory](https://access.redhat.com/errata/RHSA-2026:11077)
- **RHSA-2026:11062** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-04-27 · [advisory](https://access.redhat.com/errata/RHSA-2026:11062)
- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 8 · no fix planned: Red Hat Enterprise Linux 8 · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4786.json)