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CVE-2026-4519VulnerabilityPublished Updated

URLs · webbrowser.open() allows leading dashes

Affects MicrosoftSource GCVE Database

0
Authoritative record:CVE-2026-4519· High 7.0

Not known to be exploited · CVSS 7.0 High · fixed in 3.15.0a8 : patch Microsoft soon.

Data as of 28 Oct 2026, 08:43 UTC

CVSS 4.0 base score
7.0High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 3.15.0a8, 3.14.4, 3.13.13 +3
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 20 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Python Software FoundationCPythonAffected
  • >=3.15.0a1 <3.15.0a8
Fixed in
  • 3.15.0a8
Python Software FoundationCPythonAffected
  • >=3.14.0 <3.14.4
Fixed in
  • 3.14.4
Python Software FoundationCPythonAffected
  • >=3.13.0 <3.13.13
Fixed in
  • 3.13.13
Python Software FoundationCPythonAffected
  • >=3.12.0 <3.12.14
Fixed in
  • 3.12.14
Python Software FoundationCPythonAffected
  • >=3.11.0 <3.11.16
Fixed in
  • 3.11.16
Python Software FoundationCPythonAffected
  • <3.10.21
Fixed in
  • 3.10.21

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

References

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