# CVE-2026-98167: smb: client: fix server->total_read for compound encrypted PDUs

> A flaw in the Linux kernel SMB client allows out-of-bounds reads via truncated compound encrypted PDUs, potentially leading to information disclosure or crashes.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106017, BELL-CVE-2026-98167, DEBIAN-CVE-2026-98167, GHSA-wwfg-4wrm-v6qx, UBUNTU-CVE-2026-98167

## What is CVE-2026-98167?

CVE-2026-98167 is a memory corruption vulnerability in Linux, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

smb: client: fix server->total_read for compound encrypted PDUs

In receive_encrypted_standard(), server->total_read is left at the
full decrypted frame size when walking sub-PDUs of a compound encrypted
frame. As a result, cifs_handle_standard() passes this full size
to smb2_check_message(), causing the PDU length guards to incorrectly
validate the entire compound frame instead of the current sub-PDU.

This allows truncated non-last sub-PDUs to bypass length validation,
leading to out-of-bounds reads in smb2_get_data_area_len().

Fix this by setting server->total_read to the true length of the
current sub-PDU: next_cmd for non-last sub-PDUs, and the remaining
pdu_length for the last one.

## Which versions are affected by CVE-2026-98167?


## How do I fix CVE-2026-98167?

Apply the vendor's patch.

## Is CVE-2026-98167 being exploited?

There is no known exploitation of CVE-2026-98167 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98167 and fix it if it is affected.

What it is: CVE-2026-98167 is a memory corruption vulnerability in Linux, published on 6 Oct 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-2026-98167 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-2026-98167/ (Markdown: https://insights.sbomify.com/CVE-2026-98167/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98167
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98167
- OSV: https://osv.dev/vulnerability/CVE-2026-98167

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98167/
Summaries are generated and may contain mistakes; the official description above is the record.