About Apple security updates
For our customers' protection, Apple doesn't disclose, discuss, or confirm security issues until an investigation has occurred and patches or releases are available. Recent releases are listed on the Apple security updates page.
Apple security documents reference vulnerabilities by CVE-ID when possible.
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Swift 5.1.1 for Ubuntu
Released October 11, 2019
Available for: Ubuntu 14.04, 16.04, and 18.04
Impact: Incorrect management of file descriptors in URLSession could lead to inadvertent data disclosure
Description: This issue was addresses by updating incorrect URLSession file descriptors management logic to match Swift 5.0.