# CVE-2018-20673: Integer overflow in n/a

> An integer overflow in GNU libiberty's demangle_template function can lead to a heap-based buffer overflow, potentially allowing code execution or denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 4 Jan 2019
- **Updated:** 5 Aug 2024
- **Also known as:** ALSA-2021:4386, AZL-41601, DEBIAN-CVE-2018-20673, ECHO-4d86-022a-58ee, GHSA-jx5v-cp2v-88f2, RHSA-2021:4386, RLSA-2021:4386, ROOT-OS-DEBIAN-12-CVE-2018-20673, UBUNTU-CVE-2018-20673

## What is CVE-2018-20673?

CVE-2018-20673 is a medium-severity vulnerability in Gnu Binutils, published on 4 Jan 2019. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

The demangle_template function in cplus-dem.c in GNU libiberty, as distributed in GNU Binutils 2.31.1, contains an integer overflow vulnerability (for "Create an array for saving the template argument values") that can trigger a heap-based buffer overflow, as demonstrated by nm.

Weakness: CWE-787 (Out-of-bounds Write), CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2018-20673?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `cpp` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `gcc` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `gcc-c++` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `gcc-gdb-plugin` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `gcc-gfortran` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `gcc-offload-nvptx` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `gcc-plugin-devel` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `libitm-devel` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `libquadmath-devel` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `libstdc++-devel` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `libstdc++-docs` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `libstdc++-static` | AlmaLinux:8 | All versions | 8.5.0-3.el8.alma |
| `cpp` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `cpp-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc-c++` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc-c++-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc-gdb-plugin` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc-gdb-plugin-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc-gfortran` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc-gfortran-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc-offload-nvptx` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc-offload-nvptx-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `gcc-plugin-devel-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libasan-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libatomic-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libgcc-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libgfortran-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libgomp-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libgomp-offload-nvptx-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libitm-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libitm-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `liblsan-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libquadmath-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libquadmath-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libstdc++-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libstdc++-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |
| `libstdc++-docs` | Red Hat:enterprise_linux:8::appstream | All versions | 0:8.5.0-3.el8 |

Products: Gnu Binutils.

## How do I fix CVE-2018-20673?

Apply the vendor's patch.

## Is CVE-2018-20673 being exploited?

There is no known exploitation of CVE-2018-20673 in the wild and no public exploit code.

## Other vulnerabilities in Gnu Binutils

- [CVE-2017-7614](https://insights.sbomify.com/CVE-2017-7614/): Null dereference in n/a (critical 9.8)
- [CVE-2014-9939](https://insights.sbomify.com/CVE-2014-9939/): Memory corruption in n/a (critical 9.8)
- [CVE-2017-7226](https://insights.sbomify.com/CVE-2017-7226/): Information disclosure in n/a (critical 9.1)
- [CVE-2017-6969](https://insights.sbomify.com/CVE-2017-6969/): Information disclosure in n/a (critical 9.1)
- [CVE-2020-19726](https://insights.sbomify.com/CVE-2020-19726/): Denial of service in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-20673 and fix it if it is affected.

What it is: CVE-2018-20673 is a medium-severity vulnerability in Gnu Binutils, published on 4 Jan 2019. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-20673 in the wild and no public exploit code.

Affected product: Gnu Binutils. 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-2018-20673/ (Markdown: https://insights.sbomify.com/CVE-2018-20673/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20673
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20673
- OSV: https://osv.dev/vulnerability/CVE-2018-20673

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-20673/
Summaries are generated and may contain mistakes; the official description above is the record.