CVE-2019-15847

Name	CVE-2019-15847
Description	The POWER9 backend in GNU Compiler Collection (GCC) before version 10 could optimize multiple calls of the __builtin_darn intrinsic into a single call, thus reducing the entropy of the random number generator. This occurred because a volatile operation was not specified. For example, within a single execution of a program, the output of every __builtin_darn() call may be the same.
Source	CVE (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 severity	medium

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
gcc-7 (PTS)	buster	7.4.0-6	vulnerable
gcc-8 (PTS)	buster	8.3.0-6	vulnerable
	bullseye, sid	8.4.0-4	vulnerable
gcc-9 (PTS)	bullseye	9.3.0-15	fixed
	sid	9.3.0-17	fixed

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

Package	Type	Release	Fixed Version	Urgency
gcc-7	source	(unstable)	(unfixed)
gcc-8	source	(unstable)	(unfixed)
gcc-9	source	(unstable)	9.2.1-7	low

Notes

[buster] - gcc-7 <ignored> (minor issue, affects only POWER9 binaries)
[buster] - gcc-8 <ignored> (minor issue, affects only POWER9 binaries)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91481