CVE-2019-14842

NameCVE-2019-14842
DescriptionStructured reply is a feature of the newstyle NBD protocol allowing the server to send a reply in chunks. A bounds check which was supposed to test for chunk offsets smaller than the beginning of the request did not work because of signed/unsigned confusion. If one of these chunks contains a negative offset then data under control of the server is written to memory before the read buffer supplied by the client. If the read buffer is located on the stack then this allows the stack return address from nbd_pread() to be trivially modified, allowing arbitrary code execution under the control of the server. If the buffer is located on the heap then other memory objects before the buffer can be overwritten, which again would usually lead to arbitrary code execution.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severityhigh
Debian Bugs942215

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libnbd (PTS)bullseye1.6.1-1fixed
sid1.6.3-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libnbdsource(unstable)1.0.3-1942215

Notes

https://www.redhat.com/archives/libguestfs/2019-October/msg00060.html
https://github.com/libguestfs/libnbd/commit/f75f602a6361c0c5f42debfeea6980f698ce7f09 (1.1.4)
https://github.com/libguestfs/libnbd/commit/2c1987fc23d6d0f537edc6d4701e95a2387f7917 (stable-1.0)

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