# CVE-2019-15847: Weak cryptography in n/a

> GCC compiler optimization reduces random number entropy, potentially weakening cryptographic security for applications relying on the __builtin_darn intrinsic.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Sep 2019
- **Updated:** 14 Oct 2026
- **Also known as:** ALPINE-CVE-2019-15847, DEBIAN-CVE-2019-15847, GHSA-rf68-2835-83vw, RHSA-2020:0924, RHSA-2020:1864, RHSA-2020:2274, UBUNTU-CVE-2019-15847

## What is CVE-2019-15847?

CVE-2019-15847 is a high-severity vulnerability in Opensuse Leap, published on 2 Sep 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-331 (Insufficient Entropy)

## Which versions are affected by CVE-2019-15847?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `cpp` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `cpp-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc-c++` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc-c++-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc-gdb-plugin` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc-gdb-plugin-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc-gfortran` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc-gfortran-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc-offload-nvptx` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc-offload-nvptx-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `gcc-plugin-devel-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libasan-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libatomic-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libgcc-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libgfortran-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libgomp-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libgomp-offload-nvptx-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libitm-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libitm-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `liblsan-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libquadmath-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libquadmath-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libstdc++-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libstdc++-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libstdc++-docs` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libtsan-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `libubsan-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.3.1-5.el8 |
| `cpp-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:8.3.1-5.el8 |
| `gcc` | Red Hat:enterprise_linux:8::baseos | All versions | 0:8.3.1-5.el8 |
| `gcc-c++-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:8.3.1-5.el8 |
| `gcc-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:8.3.1-5.el8 |
| `gcc-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 0:8.3.1-5.el8 |
| `gcc-gdb-plugin-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:8.3.1-5.el8 |
| `gcc-gfortran-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:8.3.1-5.el8 |
| `gcc-offload-nvptx-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:8.3.1-5.el8 |
| `gcc-plugin-devel-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:8.3.1-5.el8 |
| `libasan` | Red Hat:enterprise_linux:8::baseos | All versions | 0:8.3.1-5.el8 |

Products: Gnu Gcc, Opensuse Leap.

## How do I fix CVE-2019-15847?

Upgrade to a fixed version.

## Is CVE-2019-15847 being exploited?

There is no known exploitation of CVE-2019-15847 in the wild and no public exploit code.

## Other vulnerabilities in Opensuse Leap

- [CVE-2018-12886](https://insights.sbomify.com/CVE-2018-12886/): Security feature bypass in n/a (high 8.1)
- [CVE-2002-2439](https://insights.sbomify.com/CVE-2002-2439/): Integer overflow in the new[] operator in gcc before 4.8.0 allows attackers to have unspecified impacts. (high 7.8)
- [CVE-2008-1367](https://insights.sbomify.com/CVE-2008-1367/): Memory corruption in n/a (high 7.5)
- [CVE-2008-1685](https://insights.sbomify.com/CVE-2008-1685/): Integer overflow in n/a (medium 6.8)
- [CVE-2021-46195](https://insights.sbomify.com/CVE-2021-46195/): Denial of service in n/a (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-15847 and fix it if it is affected.

What it is: CVE-2019-15847 is a high-severity vulnerability in Opensuse Leap, published on 2 Sep 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-15847 in the wild and no public exploit code.

Affected product: Opensuse Leap. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2019-15847/ (Markdown: https://insights.sbomify.com/CVE-2019-15847/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-15847
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-15847
- OSV: https://osv.dev/vulnerability/CVE-2019-15847

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-15847/
Summaries are generated and may contain mistakes; the official description above is the record.