# CVE-2026-31614: smb: client: fix off-by-8 bounds check in check_wsl_eas()

> A malicious SMB server can trigger an off-by-8 bounds check error in the Linux kernel SMB client, leaking up to 8 bytes of kernel heap memory.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Apr 2026
- **Updated:** 14 Jun 2026
- **Also known as:** AZL-83852, BELL-CVE-2026-31614, DEBIAN-CVE-2026-31614, GHSA-p37w-xhv5-6c8j, ROOT-OS-DEBIAN-13-CVE-2026-31614, ROOT-OS-UBUNTU-2204-CVE-2026-31614, ROOT-OS-UBUNTU-2404-CVE-2026-31614, UBUNTU-CVE-2026-31614

## What is CVE-2026-31614?

CVE-2026-31614 is a high-severity vulnerability in Linux kernel, published on 24 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

smb: client: fix off-by-8 bounds check in check_wsl_eas()

The bounds check uses (u8 *)ea + nlen + 1 + vlen as the end of the EA
name and value, but ea_data sits at offset sizeof(struct
smb2_file_full_ea_info) = 8 from ea, not at offset 0.  The strncmp()
later reads ea->ea_data[0..nlen-1] and the value bytes follow at
ea_data[nlen+1..nlen+vlen], so the actual end is ea->ea_data + nlen + 1
+ vlen.  Isn't pointer math fun?

The earlier check (u8 *)ea > end - sizeof(*ea) only guarantees the
8-byte header is in bounds, but since the last EA is placed within 8
bytes of the end of the response, the name and value bytes are read past
the end of iov.

Fix this mess all up by using ea->ea_data as the base for the bounds
check.

An "untrusted" server can use this to leak up to 8 bytes of kernel heap
into the EA name comparison and influence which WSL xattr the data is
interpreted as.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-31614?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31614?

Apply the vendor's patch.

## Is CVE-2026-31614 being exploited?

There is no known exploitation of CVE-2026-31614 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31614 and fix it if it is affected.

What it is: CVE-2026-31614 is a high-severity vulnerability in Linux kernel, published on 24 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-31614 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-31614/ (Markdown: https://insights.sbomify.com/CVE-2026-31614/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31614
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31614
- OSV: https://osv.dev/vulnerability/CVE-2026-31614

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31614/
Summaries are generated and may contain mistakes; the official description above is the record.