The process_open function in sftp-server.c in OpenSSH before 7.6 does not properly prevent write operations in readonly mode, which allows attackers to create zero-length files.
www.securityfocus.com/bid/101552
access.redhat.com/errata/RHSA-2018:0980
cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
github.com/openbsd/src/commit/a6981567e8e215acc1ef690c8dbb30f2d9b00a19
lists.debian.org/debian-lts-announce/2018/09/msg00010.html
security.gentoo.org/glsa/201801-05
security.netapp.com/advisory/ntap-20180423-0004/
www.openssh.com/txt/release-7.6
www.oracle.com/security-alerts/cpujan2020.html