High

CVE-2019-15847 — The POWER9 backend in GNU Compiler Collection (GCC) before version 10 could optimize multiple...

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.

Published Sep 2, 2019 · Updated Oct 14, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: mitre

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 3.2% (30-day exploitation probability)+13
Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

3.18%

ahead of 88% of scored CVEs · Oct 14, 2026

Affects

Gnu

Gcc and 1 more

CVSS base

7.5

High · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Gnu Gcc, Opensuse Leap).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Gnu	Gcc	< 7.5.0≥ 8.0 and < 8.4.0≥ 9.0 and < 9.3.0≥ 10.0 and < 10.1.0	Vulnerable	NIST National Vulnerability Database
Opensuse	Leap	version 15.0version 15.1	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.5	CVSS 3.1	High	3.9	3.6	nvd@nist.gov via NIST National Vulnerability Database
7.5	CVSS 3.1	High	—	—	GitHub, Inc. via GitHub Security Advisories
5.0	CVSS 2.0	Medium	10.0	2.9	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-331

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 3.18%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 14, 2026
Affected products added · gnu/gcc, opensuse/leap
Oct 14, 2026 · NIST National Vulnerability Database
CVSS changed · 7.5
Oct 14, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 14, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 14, 2026 · Alertas do Telegram
2019
CVE published
Sep 2, 2019 · mitre

Source activity

Repeated readings are counted rather than listed.

2× References added · Oct 14, 2026 – Oct 14, 2026
1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

7 on the record

gcc.gnu.org/bugzilla/show_bug.cgi
Issue Tracking, Vendor Advisory, x_refsource_MISC, NIST National Vulnerability Database
lists.opensuse.org/opensuse-security-announce/2020-05/msg00058.html
Mailing List, Third Party Advisory, vendor-advisory, x_refsource_SUSE, NIST National Vulnerability Database
cert-portal.siemens.com/productcert/html/ssa-398330.html
NIST National Vulnerability Database
lists.opensuse.org/opensuse-security-announce/2019-10/msg00057.html
Mailing List, Third Party Advisory, vendor-advisory, x_refsource_SUSE, NIST National Vulnerability Database
lists.opensuse.org/opensuse-security-announce/2019-10/msg00056.html
Mailing List, Third Party Advisory, vendor-advisory, x_refsource_SUSE, NIST National Vulnerability Database
github.com/advisories/GHSA-rf68-2835-83vw
GitHub Security Advisories
nvd.nist.gov/vuln/detail/CVE-2019-15847
GitHub Security Advisories

Elsewhere on this site

Gnu
every CVE for this vendor

CWE-331
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-31431 Linux Kernel Incorrect Resource Transfer Between Spheres Vulnerability KEV Apr 22, 2026
High CVE-2025-32463 Sudo Inclusion of Functionality from Untrusted Control Sphere Vulnerability KEV Jun 30, 2025
Medium CVE-2023-4039 GCC's-fstack-protector fails to guard dynamically-sized local variables on AArch64 Sep 13, 2023
Medium CVE-2021-3826 Buffer Errors (Improper Restriction of Operations within Memory Bounds) in Gnu Gcc Sep 1, 2022
Medium CVE-2022-27943 libiberty/rust-demangle.c in GNU GCC 11.2 allows stack consumption in demangle_const, as... Mar 26, 2022
Medium CVE-2021-46195 GCC v12.0 was discovered to contain an uncontrolled recursion via the component libiberty/rust... Jan 14, 2022

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2019-15847 is "The POWER9 backend in GNU Compiler Collection (GCC) before version 10 could optimize multiple...", rated High. It affects Gcc (Gnu); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 3.18% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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