# CVE-2026-68154: libceph: reject zero bucket types in crush_decode

> A malformed CRUSH map can cause a negative array index in the Linux kernel, leading to a denial of service.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-68154, DEBIAN-CVE-2026-68154, GHSA-33w3-5969-wxfc, UBUNTU-CVE-2026-68154

## What is CVE-2026-68154?

CVE-2026-68154 is a critical vulnerability in Linux, published on 10 Aug 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: reject zero bucket types in crush_decode

CRUSH bucket type 0 is reserved for devices.  The mapper relies on
that invariant and uses type 0 to identify leaf devices.

If crush_decode() accepts a bucket with type 0, a malformed CRUSH map
can make the mapper treat a negative bucket ID as a device and pass it
to is_out(), which then indexes the OSD weight array with a negative
value.

Reject zero bucket types while decoding the CRUSH map so the invalid
state never reaches the mapper.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-68154?


## How do I fix CVE-2026-68154?

Apply the vendor's patch.

## Is CVE-2026-68154 being exploited?

There is no known exploitation of CVE-2026-68154 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68154 and fix it if it is affected.

What it is: CVE-2026-68154 is a critical vulnerability in Linux, published on 10 Aug 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-2026-68154 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-2026-68154/ (Markdown: https://insights.sbomify.com/CVE-2026-68154/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68154
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68154
- OSV: https://osv.dev/vulnerability/CVE-2026-68154

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68154/
Summaries are generated and may contain mistakes; the official description above is the record.