# CVE-2026-64598: smb/client: Fix error code in smb2_aead_req_alloc()

> An integer overflow in the Linux kernel SMB client causes a crash when dereferencing an invalid error pointer, leading to denial of service.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 6 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-64598, DEBIAN-CVE-2026-64598, GHSA-3qwv-9mh7-f8fm, UBUNTU-CVE-2026-64598

## What is CVE-2026-64598?

CVE-2026-64598 is a high-severity vulnerability in Linux, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

smb/client: Fix error code in smb2_aead_req_alloc()

The "*num_sgs" variable is a u32 so "ERR_PTR(*num_sgs)" doesn't work.
We would have to do something similar to the previous line where it's
cast to int and then long.  However, it's simpler to store the return in
an int ret variable.

This bug would eventually result in a crash when dereference the invalid
error pointer.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-64598?


## How do I fix CVE-2026-64598?

Apply the vendor's patch.

## Is CVE-2026-64598 being exploited?

There is no known exploitation of CVE-2026-64598 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64598 and fix it if it is affected.

What it is: CVE-2026-64598 is a high-severity vulnerability in Linux, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-64598 in the wild and no public exploit code.

Affected product: Linux. 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-2026-64598/ (Markdown: https://insights.sbomify.com/CVE-2026-64598/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64598
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64598
- OSV: https://osv.dev/vulnerability/CVE-2026-64598

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64598/
Summaries are generated and may contain mistakes; the official description above is the record.