# CVE-2024-26935: scsi: core: Fix unremoved procfs host directory regression

> A logic error in the Linux kernel SCSI subsystem causes a kernel warning and resource leak when a host is allocated but not added, potentially leading to denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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:** 1 May 2024
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2024-26935, DEBIAN-CVE-2024-26935, GHSA-hxgr-6xc2-q9mv, UBUNTU-CVE-2024-26935

## What is CVE-2024-26935?

CVE-2024-26935 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 1 May 2024. 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: core: Fix unremoved procfs host directory regression

Commit fc663711b944 ("scsi: core: Remove the /proc/scsi/${proc_name}
directory earlier") fixed a bug related to modules loading/unloading, by
adding a call to scsi_proc_hostdir_rm() on scsi_remove_host(). But that led
to a potential duplicate call to the hostdir_rm() routine, since it's also
called from scsi_host_dev_release(). That triggered a regression report,
which was then fixed by commit be03df3d4bfe ("scsi: core: Fix a procfs host
directory removal regression"). The fix just dropped the hostdir_rm() call
from dev_release().

But it happens that this proc directory is created on scsi_host_alloc(),
and that function "pairs" with scsi_host_dev_release(), while
scsi_remove_host() pairs with scsi_add_host(). In other words, it seems the
reason for removing the proc directory on dev_release() was meant to cover
cases in which a SCSI host structure was allocated, but the call to
scsi_add_host() didn't happen. And that pattern happens to exist in some
error paths, for example.

Syzkaller causes that by using USB raw gadget device, error'ing on
usb-storage driver, at usb_stor_probe2(). By checking that path, we can see
that the BadDevice label leads to a scsi_host_put() after a SCSI host
allocation, but there's no call to scsi_add_host() in such path. That leads
to messages like this in dmesg (and a leak of the SCSI host proc
structure):

usb-storage 4-1:87.51: USB Mass Storage device detected
proc_dir_entry 'scsi/usb-storage' already registered
WARNING: CPU: 1 PID: 3519 at fs/proc/generic.c:377 proc_register+0x347/0x4e0 fs/proc/generic.c:376

The proper fix seems to still call scsi_proc_hostdir_rm() on dev_release(),
but guard that with the state check for SHOST_CREATED; there is even a
comment in scsi_host_dev_release() detailing that: such conditional is
meant for cases where the SCSI host was allocated but there was no calls to
{add,remove}_host(), like the usb-storage case.

This is what we propose here and with that, the error path of usb-storage
does not trigger the warning anymore.

## Which versions are affected by CVE-2024-26935?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2024-26935?

Apply the vendor's patch.

## Is CVE-2024-26935 being exploited?

There is no known exploitation of CVE-2024-26935 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-26935 and fix it if it is affected.

What it is: CVE-2024-26935 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 1 May 2024. 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-2024-26935 in the wild and no public exploit code.

Affected product: Debian Debian 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-2024-26935/ (Markdown: https://insights.sbomify.com/CVE-2024-26935/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-26935
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-26935
- OSV: https://osv.dev/vulnerability/CVE-2024-26935

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-26935/
Summaries are generated and may contain mistakes; the official description above is the record.