# CVE-2026-46024: libceph: Prevent potential null-ptr-deref in ceph_handle_auth_reply()

> A null pointer dereference in the Linux kernel's Ceph client allows a remote attacker to cause a denial of service via a crafted authentication reply.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 May 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-88563, BELL-CVE-2026-46024, DEBIAN-CVE-2026-46024, GHSA-fmw3-m5fg-w74x, ROOT-OS-DEBIAN-11-CVE-2026-46024, ROOT-OS-DEBIAN-12-CVE-2026-46024, ROOT-OS-UBUNTU-2204-CVE-2026-46024, ROOT-OS-UBUNTU-2404-CVE-2026-46024, UBUNTU-CVE-2026-46024

## What is CVE-2026-46024?

CVE-2026-46024 is a high-severity vulnerability in Linux kernel, published on 27 May 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:

libceph: Prevent potential null-ptr-deref in ceph_handle_auth_reply()

If a message of type CEPH_MSG_AUTH_REPLY contains a zero value for both
protocol and result, this is currently not treated as an error. In case
of ac->negotiating == true and ac->protocol > 0, this leads to setting
ac->protocol = 0 and ac->ops = NULL. Thereafter, the check for
ac->protocol != protocol returns false, and init_protocol() is not
called. Subsequently, ac->ops->handle_reply() is called, which leads to
a null pointer dereference, because ac->ops is still NULL.

This patch changes the check for ac->protocol != protocol to
!ac->protocol, as this also includes the case when the protocol was set
to zero in the message. This causes the message to be treated as
containing a bad auth protocol.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-46024?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46024?

Apply the vendor's patch.

## Is CVE-2026-46024 being exploited?

There is no known exploitation of CVE-2026-46024 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-2026-46024 and fix it if it is affected.

What it is: CVE-2026-46024 is a high-severity vulnerability in Linux kernel, published on 27 May 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-2026-46024 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-2026-46024/ (Markdown: https://insights.sbomify.com/CVE-2026-46024/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46024
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46024
- OSV: https://osv.dev/vulnerability/CVE-2026-46024

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46024/
Summaries are generated and may contain mistakes; the official description above is the record.