# CVE-2023-28320: Race condition in https://github.com/curl/curl

> A race condition in curl's synchronous resolver can cause crashes in multi-threaded applications using specific build configurations.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/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:** 26 May 2023
- **Updated:** 15 Jan 2025
- **Also known as:** ALPINE-CVE-2023-28320, AZL-26790, AZL-26793, AZL-26809, AZL-26813, AZL-34605, AZL-38926, CLEANSTART-2026-ON18774, CURL-CVE-2023-28320, DEBIAN-CVE-2023-28320, GHSA-c8wj-435x-f2cc, JLSEC-2026-408

## What is CVE-2023-28320?

CVE-2023-28320 is a medium-severity vulnerability in Apple Macos, published on 26 May 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A denial of service vulnerability exists in curl <v8.1.0 in the way libcurl provides several different backends for resolving host names, selected at build time. If it is built to use the synchronous resolver, it allows name resolves to time-out slow operations using `alarm()` and `siglongjmp()`. When doing this, libcurl used a global buffer that was not mutex protected and a multi-threaded application might therefore crash or otherwise misbehave.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2023-28320?

It affects 8 products.


Products: Apple Macos, Haxx Curl, Netapp Clustered Data Ontap, Netapp H300s Firmware, Netapp H410s Firmware, Netapp H500s Firmware, Netapp H700s Firmware, Netapp Ontap Antivirus Connector.

## How do I fix CVE-2023-28320?

Upgrade to a fixed version.

## Is CVE-2023-28320 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-28320 exists.

## Other vulnerabilities in Apple Macos

- [CVE-2026-65400](https://insights.sbomify.com/CVE-2026-65400/): Apple macOS Improper Authentication (critical 9.8, exploited in the wild)
- [CVE-2024-44146](https://insights.sbomify.com/CVE-2024-44146/): Security feature bypass in macOS (critical 10.0)
- [CVE-2024-44148](https://insights.sbomify.com/CVE-2024-44148/): Security feature bypass in macOS (critical 10.0)
- [CVE-2023-38586](https://insights.sbomify.com/CVE-2023-38586/): Security feature bypass in macOS (critical 10.0)
- [CVE-2023-40455](https://insights.sbomify.com/CVE-2023-40455/): Security feature bypass in macOS (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-28320 and fix it if it is affected.

What it is: CVE-2023-28320 is a medium-severity vulnerability in Apple Macos, published on 26 May 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-28320 exists.

Affected product: Apple Macos. 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-2023-28320/ (Markdown: https://insights.sbomify.com/CVE-2023-28320/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28320
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28320
- OSV: https://osv.dev/vulnerability/CVE-2023-28320

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28320/
Summaries are generated and may contain mistakes; the official description above is the record.