What’s Vulnerable › Vulnerabilities

CVE-2019-15847

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2019-09-02 · updated 2026-10-14
• Weakness: CWE-331

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.

Affected products

• GNU GCC: before 7.5.0; from 8.0 before 8.4.0; from 9.0 before 9.3.0; from 10.0 before 10.1.0 — fixed in 10.1.0, 7.5.0, 8.4.0, 9.3.0
• openSUSE Leap: 15.0, 15.1

How to fix

Upgrade to a fixed version: GNU GCC 10.1.0, 7.5.0, 8.4.0, 9.3.0. Check the vendor advisory for mitigations.

References

• http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00056.html
• http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00057.html
• http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00058.html
• https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91481
• http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00056.html
• http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00057.html
• http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00058.html
• https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91481
• https://cert-portal.siemens.com/productcert/html/ssa-398330.html

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