# CVE-2023-39323: Arbitrary code execution during build via line directives in cmd/go

> Attackers can execute arbitrary code during Go builds by using line directives to bypass compiler restrictions, affecting developers using the Go toolchain.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 5 Oct 2023
- **Updated:** 12 Jun 2025
- **Also known as:** AZL-31107, AZL-37358, AZL-37389, AZL-52845, AZL-78984, AZL-98871, BELL-CVE-2023-39323, BIT-golang-2023-39323, DEBIAN-CVE-2023-39323, GHSA-679v-hh23-h5jh, GO-2023-2095, MINI-7pfc-8q48-vpr7, SUSE-SU-2023:4017-1, SUSE-SU-2023:4018-1, UBUNTU-CVE-2023-39323, openSUSE-SU-2024:13306-1, openSUSE-SU-2024:13307-1

## What is CVE-2023-39323?

CVE-2023-39323 is a high-severity code injection vulnerability in Fedoraproject Fedora, published on 5 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Line directives ("//line") can be used to bypass the restrictions on "//go:cgo_" directives, allowing blocked linker and compiler flags to be passed during compilation. This can result in unexpected execution of arbitrary code when running "go build". The line directive requires the absolute path of the file in which the directive lives, which makes exploiting this issue significantly more complex.

## Which versions are affected by CVE-2023-39323?

2 open source packages ship an affected version, including golang and toolchain. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `golang` | Bitnami | All versions | 1.20.9, 1.21.2 |
| `toolchain` | Go | All versions | 1.20.9, 1.21.2 |
| `go1.20` | SUSE:Linux Enterprise Module for Development Tools 15 SP4 | All versions | 1.20.9-150000.1.26.1 |
| `go1.21` | SUSE:Linux Enterprise Module for Development Tools 15 SP4 | All versions | 1.21.2-150000.1.9.1 |
| `go1.20` | SUSE:Linux Enterprise Module for Development Tools 15 SP5 | All versions | 1.20.9-150000.1.26.1 |
| `go1.21` | SUSE:Linux Enterprise Module for Development Tools 15 SP5 | All versions | 1.21.2-150000.1.9.1 |
| `go1.20` | openSUSE:Leap 15.4 | All versions | 1.20.9-150000.1.26.1 |
| `go1.21` | openSUSE:Leap 15.4 | All versions | 1.21.2-150000.1.9.1 |
| `go1.20` | openSUSE:Leap 15.5 | All versions | 1.20.9-150000.1.26.1 |
| `go1.21` | openSUSE:Leap 15.5 | All versions | 1.21.2-150000.1.9.1 |
| `go1.20` | openSUSE:Tumbleweed | All versions | 1.20.9-1.1 |
| `go1.21` | openSUSE:Tumbleweed | All versions | 1.21.2-1.1 |

Products: Fedoraproject Fedora, Golang Go.

## How do I fix CVE-2023-39323?

Upgrade golang to a fixed version for your release line: 1.20.9 or 1.21.2.

## Is CVE-2023-39323 being exploited?

There is no known exploitation of CVE-2023-39323 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-39323 and fix it if it is affected.

What it is: CVE-2023-39323 is a high-severity code injection vulnerability in Fedoraproject Fedora, published on 5 Oct 2023. 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-2023-39323 in the wild and no public exploit code.

Affected packages and fixed versions:
- golang (Bitnami): affected all versions; fixed in 1.20.9, 1.21.2
- toolchain (Go): affected all versions; fixed in 1.20.9, 1.21.2

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-2023-39323/ (Markdown: https://insights.sbomify.com/CVE-2023-39323/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-39323
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-39323
- OSV: https://osv.dev/vulnerability/CVE-2023-39323

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-39323/
Summaries are generated and may contain mistakes; the official description above is the record.