CVE-2019-15847

gcc: POWER9 "DARN" RNG intrinsic produces repeated output

Published Sep 2, 2019 CVSS 3.1 · 7.5 High EPSS 3.2% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2019-6763 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.
Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Oct 14, 2026, 6:50 AM
Reserved
Sep 2, 2019, 12:00 AM
Status
Modified
Published
Sep 2, 2019, 11:15 PM
Modified
Oct 14, 2026, 7:16 AM
Severity
Moderate
Public date
Sep 2, 2019, 12:00 AM