# CVE-2026-39873: Memory corruption in macOS

> A memory handling flaw in macOS allows a malicious SMB server to cause unexpected system termination, requiring users to apply security updates.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/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:** No
- **Published:** 27 Jul 2026
- **Updated:** 28 Jul 2026
- **Also known as:** GHSA-2pcr-98qw-8jgc

## What is CVE-2026-39873?

CVE-2026-39873 is a critical memory corruption vulnerability in Apple Macos, published on 27 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The issue was addressed with improved memory handling. This issue is fixed in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6. Connecting to a malicious SMB server may lead to unexpected system termination.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-39873?

It affects 1 product.


Products: Apple Macos.

## How do I fix CVE-2026-39873?

No fix has been published for CVE-2026-39873 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-39873 being exploited?

There is no known exploitation of CVE-2026-39873 in the wild and no public exploit code.

## 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-2026-39873 and fix it if it is affected.

What it is: CVE-2026-39873 is a critical memory corruption vulnerability in Apple Macos, published on 27 Jul 2026. 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-2026-39873 in the wild and no public exploit code.

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-2026-39873/ (Markdown: https://insights.sbomify.com/CVE-2026-39873/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-39873
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-39873
- OSV: https://osv.dev/vulnerability/CVE-2026-39873

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-39873/
Summaries are generated and may contain mistakes; the official description above is the record.