Python CPython up to 3.14.x webbrowser.open command injection

CVSS Meta Temp Score
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CTI Interest Score
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7.0$0-$5k0.00

Summaryinfo

A vulnerability was found in Python CPython up to 3.14.x and classified as critical. This impacts the function webbrowser.open. Executing a manipulation can lead to command injection. This vulnerability is handled as CVE-2026-4786. The attack can be executed remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Python CPython up to 3.14.x. This vulnerability affects the function webbrowser.open. The manipulation with an unknown input leads to a command injection vulnerability. The CWE definition for the vulnerability is CWE-77. The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-4786 since 03/24/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1202.

The vulnerability scanner Nessus provides a plugin with the ID 307390 (Fedora 45 : python3.12 (2026-2dfcf9d705)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.15.0 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (307390) and CERT Bund (WID-SEC-2026-1087). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

  • Debian Linux
  • Red Hat Enterprise Linux
  • Fedora Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • IBM SPSS
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Python

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Command injection
CWE: CWE-77 / CWE-74 / CWE-707
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 307390
Nessus Name: Fedora 45 : python3.12 (2026-2dfcf9d705)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: CPython 3.15.0
Patch: github.com

Timelineinfo

03/24/2026 CVE reserved
04/14/2026 +20 days Advisory disclosed
04/14/2026 +0 days VulDB entry created
07/17/2026 +94 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: 148169
Status: Confirmed

CVE: CVE-2026-4786 (🔒)
GCVE (CVE): GCVE-0-2026-4786
GCVE (VulDB): GCVE-100-357256
CERT Bund: WID-SEC-2026-1087 - CPython: Mehrere Schwachstellen

Entryinfo

Created: 04/14/2026 07:58
Updated: 07/17/2026 10:03
Changes: 04/14/2026 07:58 (70), 04/18/2026 09:16 (2), 05/04/2026 00:37 (7), 05/20/2026 13:50 (1), 07/17/2026 10:03 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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