Improper input validation in Python
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. New behavior rejects leading dashes. Users are recommended to sanitize URLs prior to passing to webbrowser.open().
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.3 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (30.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 30.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Python — versions 3.15.0
- Python Software Foundation Cpython — versions 3.14.0, 0, 3.13.0
Weakness classification (CWE)
References
- github.com/python/cpython/pull/143931 (Patch, patch, Issue Tracking)
- github.com/python/cpython/issues/143930 (issue-tracking, Patch, Issue Tracking)
- mail.python.org/archives/list/security-announce@python.org/thread/AY5NDSS433JK5… (vendor-advisory, Vendor Advisory)
- github.com/python/cpython/commit/43fe06b96f6a6cf5cfd5bdab20b8649374956866 (Patch, patch)
- github.com/python/cpython/commit/82a24a4442312bdcfc4c799885e8b3e00990f02b (Patch, patch)
- github.com/python/cpython/commit/9669a912a0e329c094e992204d6bdb8787024d76 (Patch, patch)
- github.com/python/cpython/commit/ad4d5ba32af4d80b0dfa2ba9d8203bfb219e60a5 (Patch, patch)
- github.com/python/cpython/commit/ceac1efc66516ac387eef2c9a0ce671895b44f03 (Patch, patch)
- github.com/python/cpython/commit/cbba6119391112aba9c5aebf7b94aea447922c48 (Patch, patch)
- github.com/python/cpython/commit/3681d47a440865aead912a054d4599087b4270dd (Patch, patch)
Frequently asked questions
- What is CVE-2026-4519?
- CVE-2026-4519 is a low-severity vulnerability in Python, classified under Improper Input Validation. CVSS score: 3.3/10. Published 2026-03-20.
- How severe is CVE-2026-4519?
- Low severity. CVSS v3 base score is 3.3 out of 10.