CWE-77 in Python Software Foundation CPython (CVE-2026-4786)
CVE-2026-4786 is a high-severity vulnerability in the Python Software Foundation's CPython implementation. It involves command injection via the webbrowser.open() API when URLs contain the string "%action", allowing potential arbitrary code execution. This issue is a bypass of an incomplete mitigation for CVE-2026-4519. The vulnerability affects certain versions of CPython and has been addressed by Red Hat in updated packages for their Extended Life Cycle Support for RHEL 6. No known exploits are reported in the wild.
AI Analysis
Technical Summary
CVE-2026-4786 is a command injection vulnerability (CWE-77) in CPython's webbrowser.open() API. The vulnerability arises because the mitigation for a previous related issue (CVE-2026-4519) was incomplete, allowing an attacker to bypass it if the URL contains "%action". This can lead to arbitrary code execution via shell command injection. The vulnerability affects CPython versions including 0, 3.14.0a1, and 3.15.0a1. Red Hat has issued security advisories and updates to address this vulnerability in their Extended Life Cycle Support for RHEL 6, providing patched python packages. The CVSS v4.0 base score is 7.0, indicating high severity, with local attack vector, low attack complexity, partial user interaction, and high impact on confidentiality and integrity.
Potential Impact
Successful exploitation of this vulnerability could allow an attacker to execute arbitrary commands on the affected system via the webbrowser.open() API in CPython. This could lead to unauthorized code execution, potentially compromising system integrity and confidentiality. The vulnerability specifically affects local users who can supply crafted URLs containing "%action" to bypass previous mitigations. There are no reports of known exploits in the wild at this time.
Mitigation Recommendations
Red Hat has released security updates for python packages in Red Hat Enterprise Linux 6 Extended Life Cycle Support to address CVE-2026-4786. Applying these official patches will remediate the vulnerability. Users should update to the fixed package versions as described in the Red Hat advisory (RHSA-2026:22144). No additional mitigation steps are indicated beyond applying the vendor-provided updates.
CWE-77 in Python Software Foundation CPython (CVE-2026-4786)
Description
CVE-2026-4786 is a high-severity vulnerability in the Python Software Foundation's CPython implementation. It involves command injection via the webbrowser.open() API when URLs contain the string "%action", allowing potential arbitrary code execution. This issue is a bypass of an incomplete mitigation for CVE-2026-4519. The vulnerability affects certain versions of CPython and has been addressed by Red Hat in updated packages for their Extended Life Cycle Support for RHEL 6. No known exploits are reported in the wild.
CVSS v4.0
Score 7.0high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-4786 is a command injection vulnerability (CWE-77) in CPython's webbrowser.open() API. The vulnerability arises because the mitigation for a previous related issue (CVE-2026-4519) was incomplete, allowing an attacker to bypass it if the URL contains "%action". This can lead to arbitrary code execution via shell command injection. The vulnerability affects CPython versions including 0, 3.14.0a1, and 3.15.0a1. Red Hat has issued security advisories and updates to address this vulnerability in their Extended Life Cycle Support for RHEL 6, providing patched python packages. The CVSS v4.0 base score is 7.0, indicating high severity, with local attack vector, low attack complexity, partial user interaction, and high impact on confidentiality and integrity.
Potential Impact
Successful exploitation of this vulnerability could allow an attacker to execute arbitrary commands on the affected system via the webbrowser.open() API in CPython. This could lead to unauthorized code execution, potentially compromising system integrity and confidentiality. The vulnerability specifically affects local users who can supply crafted URLs containing "%action" to bypass previous mitigations. There are no reports of known exploits in the wild at this time.
Mitigation Recommendations
Red Hat has released security updates for python packages in Red Hat Enterprise Linux 6 Extended Life Cycle Support to address CVE-2026-4786. Applying these official patches will remediate the vulnerability. Users should update to the fixed package versions as described in the Red Hat advisory (RHSA-2026:22144). No additional mitigation steps are indicated beyond applying the vendor-provided updates.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:10711
- Cve Count
- 2
- Additional Cves
- ["CVE-2026-6100"]
- Cvss Version
- null
Threat ID: 6a175eefe29bf47b50edd97d
Added to database: 05/27/2026, 21:15:27 UTC
Last enriched: 07/15/2026, 15:33:11 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 79
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