CVE-2026-4519 webbrowser.open() allows leading dashes in URLs

What is CVE-2026-4519?

CVE-2026-4519 is a high-severity command injection vulnerability in Python Python, published on 20 Mar 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official 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().

Weakness: CWE-88, CWE-20

Which versions are affected by CVE-2026-4519?

It affects 1 product.

Products include Python Python.

How do I fix CVE-2026-4519?

Apply the vendor's patch.

Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.

Is CVE-2026-4519 being exploited?

There is no known exploitation of CVE-2026-4519 in the wild and no public exploit code.

Other vulnerabilities in Python Python

• CVE-2008-5031 Integer overflow in n/a Critical 10.0
• CVE-2014-4650 Path traversal in n/a Critical 9.8
• CVE-2016-5636 Integer overflow in n/a Critical 9.8
• CVE-2007-4559 Path traversal in n/a Critical 9.8
• CVE-2017-17522 Command injection in n/a High 8.8

All Python Python vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2026-4519, ALSA-2026:6256, ALSA-2026:6281, ALSA-2026:6283, ALSA-2026:6285, ALSA-2026:6286 and 58 more.