# CVE-2026-98170: smb: client: fix OOB struct field reads in move_smb2_ea_to_cifs()

> Out-of-bounds reads in the Linux kernel SMB client allow attackers to cause denial of service or disclose memory contents via malformed server responses.

- **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:** 21 Oct 2026
- **Also known as:** AZL-105975, BELL-CVE-2026-98170, DEBIAN-CVE-2026-98170, GHSA-qx7m-524h-7684, UBUNTU-CVE-2026-98170

## What is CVE-2026-98170?

CVE-2026-98170 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 OOB struct field reads in move_smb2_ea_to_cifs()

In move_smb2_ea_to_cifs(), the while (src_size > 0) loop condition is
insufficient. It allows iteration to continue even if the remaining
src_size is too small to contain a complete smb2_ea_info structure.
Consequently, reads of ea_name_length and ea_value_length can occur
out-of-bounds.

Fix this by ensuring src_size >= sizeof(*src) before attempting to read
any structure fields. Additionally, reject any next_entry_offset that is
smaller than sizeof(*src) or that would advance the pointer beyond the
available buffer.

Note that for calls where the server returns a malformed EA list, the
error returned to userspace changes from -ENODATA (getxattr) or
-ERANGE (listxattr) to -EIO. This correctly signals a server protocol
error rather than misleadingly indicating "attribute not present" or
"output buffer too small".

## Which versions are affected by CVE-2026-98170?


## How do I fix CVE-2026-98170?

Apply the vendor's patch.

## Is CVE-2026-98170 being exploited?

There is no known exploitation of CVE-2026-98170 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98170 and fix it if it is affected.

What it is: CVE-2026-98170 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-2026-98170 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-2026-98170/ (Markdown: https://insights.sbomify.com/CVE-2026-98170/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98170
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98170
- OSV: https://osv.dev/vulnerability/CVE-2026-98170

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98170/
Summaries are generated and may contain mistakes; the official description above is the record.