Patch a directory traversal vulnerability in the KTNEF parser.
Backported from
https://commits.kde.org/ktnef/4ff38aa15487d69021aacad4b078500f77fb4ae8
Security announcement:
https://www.kde.org/info/security/advisory-20170227-1.txt
MFH: 2017Q1
Security: e550fc62-069a-11e7-8e3e-5453ed2e2b49