CVE-2026-4519
The webbrowser.open() API would accept leading dashes in the URL which could be handled as command line options for certain web browsers.
Published Mar 20, 2026 · corrected/updated Aug 13, 2026 · Red Hat python · evidence confidence high
A flaw was found in Python. The API, used to launch web browsers, does not properly sanitize input. This allows a remote attacker to craft a malicious URL containing leading dashes. When such a URL is opened, certain web browsers may interpret these dashes as command-line options, which could lead to unexpected behavior, information disclosure, or potentially arbitrary code execution, impacting the integrity of the system.
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-4519 is a high public vulnerability record for Red Hat python. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether Red Hat python is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: python/python; python/python (3.15.0). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 7.1. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-20, CWE-88. Sources contributing to this record: csaf, csaf, cve_org, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Mar 20, 2026 · NIST NVD
Detected
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().
Aug 13, 2026 · NIST NVD
Updated
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().
Affected
- cpe python/pythonversion unspecified
- cpe python/python3.15.0
Sources
- CSAF AdvisoriesVendor advisoryRHSA-2026:9705:CVE-2026-4519
A flaw was found in Python. The API, used to launch web browsers, does not properly sanitize input. This allows a remote attacker to craft a malicious URL containing leading dashes. When such a URL is opened, certain web browsers may interpret these dashes as command-line options
security.access.redhat.com - CSAF AdvisoriesVendor advisoryRHSA-2026:9745:CVE-2026-4519
A flaw was found in Python. The API, used to launch web browsers, does not properly sanitize input. This allows a remote attacker to craft a malicious URL containing leading dashes. When such a URL is opened, certain web browsers may interpret these dashes as command-line options
security.access.redhat.com - CVE.orgVulnerability recordCVE-2026-4519
Official CVE identifier
cve.org - NIST NVDVulnerability recordCVE-2026-4519
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().
nvd.nist.gov