# CVE-2026-31464: scsi: ibmvfc: Fix OOB access in ibmvfc_discover_targets_done()

> A malicious VIO server can trigger an out-of-bounds read in the ibmvfc driver, leaking kernel memory to the attacker.

- **Severity:** High 8.1 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Apr 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-31464, DEBIAN-CVE-2026-31464, GHSA-5q5q-53h5-v4v4, ROOT-OS-DEBIAN-11-CVE-2026-31464, ROOT-OS-DEBIAN-12-CVE-2026-31464, ROOT-OS-DEBIAN-13-CVE-2026-31464, ROOT-OS-UBUNTU-2204-CVE-2026-31464, ROOT-OS-UBUNTU-2404-CVE-2026-31464, UBUNTU-CVE-2026-31464

## What is CVE-2026-31464?

CVE-2026-31464 is a high-severity vulnerability in Linux kernel, published on 22 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:

scsi: ibmvfc: Fix OOB access in ibmvfc_discover_targets_done()

A malicious or compromised VIO server can return a num_written value in the
discover targets MAD response that exceeds max_targets. This value is
stored directly in vhost->num_targets without validation, and is then used
as the loop bound in ibmvfc_alloc_targets() to index into disc_buf[], which
is only allocated for max_targets entries. Indices at or beyond max_targets
access kernel memory outside the DMA-coherent allocation.  The
out-of-bounds data is subsequently embedded in Implicit Logout and PLOGI
MADs that are sent back to the VIO server, leaking kernel memory.

Fix by clamping num_written to max_targets before storing it.

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

## Which versions are affected by CVE-2026-31464?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31464?

Apply the vendor's patch.

## Is CVE-2026-31464 being exploited?

There is no known exploitation of CVE-2026-31464 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-2026-31464 and fix it if it is affected.

What it is: CVE-2026-31464 is a high-severity vulnerability in Linux kernel, published on 22 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-2026-31464 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-2026-31464/ (Markdown: https://insights.sbomify.com/CVE-2026-31464/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31464
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31464
- OSV: https://osv.dev/vulnerability/CVE-2026-31464

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31464/
Summaries are generated and may contain mistakes; the official description above is the record.