Is CVE-2026-4519 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-4519 being exploited in the wild.

How severe is CVE-2026-4519?

Low severity, with a CVSS score of 3.3, published 20 March 2026.

Which products and versions are affected?

Python Software Foundation CPython 3.10, 3.13, 3.14.

Is there a fix for CVE-2026-4519?

A patch was published on 2026-01-16: Initial security fix commits in CPython repository Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-4519 attacked?

It is attacked with local access or over the network, in a software library.

Am I affected by CVE-2026-4519?

Check whether you run Python Software Foundation CPython at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-4519: Python CPython argument injection in webbrowser.open

CVE-2026-4519 · Severity: low · CVSS 3.3 · Published 2026-03-20

A vulnerability in the Python 'webbrowser' module could allow a malicious URL to be misinterpreted as a command-line instruction. If an application passes an untrusted URL starting with a dash to this module, it might trigger unintended browser behaviors or settings changes rather than simply opening a website. This could potentially be used to bypass security prompts or interfere with how the browser handles the request.

Technologies: Python Software Foundation CPython. Vendors: Python Software Foundation.

Quick answers

Is CVE-2026-4519 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-4519 being exploited in the wild.
How severe is CVE-2026-4519?: Low severity, with a CVSS score of 3.3, published 20 March 2026.
Which products and versions are affected?: Python Software Foundation CPython 3.10, 3.13, 3.14.
Is there a fix for CVE-2026-4519?: A patch was published on 2026-01-16: Initial security fix commits in CPython repository Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-4519 attacked?: It is attacked with local access or over the network, in a software library.
Am I affected by CVE-2026-4519?: Check whether you run Python Software Foundation CPython at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A command injection or argument injection vulnerability exists in the Python 'webbrowser' module. The 'webbrowser.open()' function fails to properly validate or sanitize URLs that begin with a dash ('-'). When these URLs are passed to the underlying shell or process execution call to launch a browser, the leading dash causes the browser to interpret the URL as a command-line argument/flag rather than a web address. Attackers who can influence the URL passed to this API could potentially execute arbitrary browser commands. The fix involves updating the module to reject URLs with leading dashes, and developers are advised to sanitize inputs before passing them to this function.

Affected products

Python Software Foundation CPython 3.10, 3.13, 3.14

Timeline

2026-03-20: advisory
2026-01-16: patched: Initial security fix commits in CPython repository

References

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