CVE-2026-4519: Vulnerability in Python Software Foundation CPython
The webbrowser.open() API would accept leading dashes in the URL which could be handled as command line options for certain web browsers. New behavior rejects leading dashes. Users are recommended to sanitize URLs prior to passing to webbrowser.open().
AI Analysis
Technical Summary
The vulnerability in CPython's webbrowser.open() API arises because it accepts URLs starting with leading dashes, which some web browsers may interpret as command line options. This can lead to unexpected or unsafe behavior when opening URLs. The Python Software Foundation has updated the API to reject URLs with leading dashes. Users should sanitize input URLs to avoid passing potentially malicious strings. The vulnerability is tracked as CVE-2026-4519 with a CVSS 4.0 score of 7.0 (high severity).
Potential Impact
If exploited, this vulnerability could allow an attacker to influence how web browsers interpret URLs passed via the webbrowser.open() API, potentially leading to unintended command line option processing. This could affect the security context in which the browser operates. However, no known exploits are currently reported in the wild.
Mitigation Recommendations
No official patch or fix is currently documented. Users should sanitize URLs to ensure they do not start with leading dashes before passing them to webbrowser.open(). Monitor the Python Software Foundation advisories for updates or official fixes.
CVE-2026-4519: Vulnerability in Python Software Foundation CPython
Description
The webbrowser.open() API would accept leading dashes in the URL which could be handled as command line options for certain web browsers. New behavior rejects leading dashes. Users are recommended to sanitize URLs prior to passing to webbrowser.open().
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in CPython's webbrowser.open() API arises because it accepts URLs starting with leading dashes, which some web browsers may interpret as command line options. This can lead to unexpected or unsafe behavior when opening URLs. The Python Software Foundation has updated the API to reject URLs with leading dashes. Users should sanitize input URLs to avoid passing potentially malicious strings. The vulnerability is tracked as CVE-2026-4519 with a CVSS 4.0 score of 7.0 (high severity).
Potential Impact
If exploited, this vulnerability could allow an attacker to influence how web browsers interpret URLs passed via the webbrowser.open() API, potentially leading to unintended command line option processing. This could affect the security context in which the browser operates. However, no known exploits are currently reported in the wild.
Mitigation Recommendations
No official patch or fix is currently documented. Users should sanitize URLs to ensure they do not start with leading dashes before passing them to webbrowser.open(). Monitor the Python Software Foundation advisories for updates or official fixes.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- PSF
- Date Reserved
- 2026-03-20T15:01:11.126Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 69bd66a5e32a4fbe5fa5cd32
Added to database: 3/20/2026, 3:24:21 PM
Last enriched: 4/15/2026, 11:42:49 AM
Last updated: 4/29/2026, 5:03:11 AM
Views: 158
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