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CVE-2019-15847

26
FAUCET Score

CVE-2019-15847 affects GNU Compiler Collection (GCC) versions prior to 10, specifically its POWER9 backend, where multiple calls to the __builtin_darn intrinsic could be optimized into a single call, leading to reduced random number generator entropy. This vulnerability has a CVSS score of 7.5 (HIGH), indicating a network-exploitable flaw with low attack complexity that could result in high confidentiality impact by making random numbers predictable. While no active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB) has been identified, there is some community discussion and media coverage, suggesting awareness of the issue.

Impacted Technologies

VendorProductVersion(s)CPE
< 7.5.0CPE matchmatch criteria
cpe:2.3:a:gnu:gcc:*:*:*:*:*:*:*:*
>= 8.0, < 8.4.0CPE matchmatch criteria
cpe:2.3:a:gnu:gcc:*:*:*:*:*:*:*:*
>= 9.0, < 9.3.0CPE matchmatch criteria
cpe:2.3:a:gnu:gcc:*:*:*:*:*:*:*:*
>= 10.0, < 10.1.0CPE matchmatch criteria
cpe:2.3:a:gnu:gcc:*:*:*:*:*:*:*:*
15.0CPE matchmatch criteria
cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.21%
Probability of exploitation in next 30 days
EPSS Percentile
86.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0321 is in the 76th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (13)

microsoftpatch availablevia msrc
Product: 17017-16820Fixed in: 9.1.0-7
microsoftpatch availablevia msrc
Product: cm1 gcc 9.1.0-7 on CBL Mariner 1.0Fixed in: 9.1.0-7
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 x64Fixed in: 9.1.0-7
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 ARMFixed in: 9.1.0-7
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUSFixed in: devtoolset-8-gcc-0:8.3.1-3.2.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUSFixed in: devtoolset-8-gcc-0:8.3.1-3.2.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: gcc-0:8.3.1-5.el8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUSFixed in: devtoolset-8-gcc-0:8.3.1-3.2.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUSFixed in: devtoolset-9-gcc-0:9.3.1-2.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUSFixed in: devtoolset-9-gcc-0:9.3.1-2.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 6Fixed in: devtoolset-8-gcc-0:8.3.1-3.2.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: devtoolset-8-gcc-0:8.3.1-3.2.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: devtoolset-9-gcc-0:9.3.1-2.el7
View patch

Vendor Advisories (3)

microsoft2020-Aug/CVE-2019-15847

CVE-2019-15847

Aug 11, 2020
microsoft2019-Sep/CVE-2019-15847Important

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.

Sep 10, 2019
redhatCVE-2019-15847Moderate

gcc: POWER9 "DARN" RNG intrinsic produces repeated output

Sep 2, 2019

References

lists.opensuse.org / opensuse-security-announce/2019-10/msg00056.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2019-10/msg00057.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-05/msg00058.html
Mailing ListThird Party Advisory
gcc.gnu.org / bugzilla/show_bug.cgi
Issue TrackingVendor Advisory