# CVE-2026-23032: null_blk: fix kmemleak by releasing references to fault configfs items

> A memory leak in the Linux kernel null_blk driver allows local attackers to exhaust kernel memory, causing denial of service.

- **Severity:** Not scored
- **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:** 31 Jan 2026
- **Updated:** 2 Jun 2026
- **Also known as:** AZL-77214, BELL-CVE-2026-23032, DEBIAN-CVE-2026-23032, GHSA-jq2q-j87r-jrqv, ROOT-OS-UBUNTU-2404-CVE-2026-23032, UBUNTU-CVE-2026-23032

## What is CVE-2026-23032?

CVE-2026-23032 is a memory corruption vulnerability in Linux, published on 31 Jan 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:

null_blk: fix kmemleak by releasing references to fault configfs items

When CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION is enabled, the null-blk
driver sets up fault injection support by creating the timeout_inject,
requeue_inject, and init_hctx_fault_inject configfs items as children
of the top-level nullbX configfs group.

However, when the nullbX device is removed, the references taken to
these fault-config configfs items are not released. As a result,
kmemleak reports a memory leak, for example:

unreferenced object 0xc00000021ff25c40 (size 32):
  comm "mkdir", pid 10665, jiffies 4322121578
  hex dump (first 32 bytes):
    69 6e 69 74 5f 68 63 74 78 5f 66 61 75 6c 74 5f  init_hctx_fault_
    69 6e 6a 65 63 74 00 88 00 00 00 00 00 00 00 00  inject..........
  backtrace (crc 1a018c86):
    __kmalloc_node_track_caller_noprof+0x494/0xbd8
    kvasprintf+0x74/0xf4
    config_item_set_name+0xf0/0x104
    config_group_init_type_name+0x48/0xfc
    fault_config_init+0x48/0xf0
    0xc0080000180559e4
    configfs_mkdir+0x304/0x814
    vfs_mkdir+0x49c/0x604
    do_mkdirat+0x314/0x3d0
    sys_mkdir+0xa0/0xd8
    system_call_exception+0x1b0/0x4f0
    system_call_vectored_common+0x15c/0x2ec

Fix this by explicitly releasing the references to the fault-config
configfs items when dropping the reference to the top-level nullbX
configfs group.

## Which versions are affected by CVE-2026-23032?


## How do I fix CVE-2026-23032?

Apply the vendor's patch.

## Is CVE-2026-23032 being exploited?

There is no known exploitation of CVE-2026-23032 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23032 and fix it if it is affected.

What it is: CVE-2026-23032 is a memory corruption vulnerability in Linux, published on 31 Jan 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-2026-23032 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-2026-23032/ (Markdown: https://insights.sbomify.com/CVE-2026-23032/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23032
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23032
- OSV: https://osv.dev/vulnerability/CVE-2026-23032

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23032/
Summaries are generated and may contain mistakes; the official description above is the record.