# CVE-2026-68158: libceph: Fix multiplication overflow in decode_new_up_state_weight()

> A malicious Ceph OSD map message can trigger an integer overflow leading to out-of-bounds memory access, potentially causing crashes or information disclosure.

- **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-2026-68158, DEBIAN-CVE-2026-68158, GHSA-jg8v-h49p-mvhw, UBUNTU-CVE-2026-68158

## What is CVE-2026-68158?

CVE-2026-68158 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: Fix multiplication overflow in decode_new_up_state_weight()

If a message of type CEPH_MSG_OSD_MAP contains a (maliciously) corrupted
osdmap, out-of-bounds memory accesses may occur in
decode_new_up_state_weight(). This happens because the bounds check for
the new_state part is based on calculating its length depending on a len
value read from the incoming message. This calculation may overflow
leading to an incorrect bounds check. Subsequently, out-of-bounds reads
may occur when decoding this part.

This patch switches the multiplication to use check_mul_overflow() to
abort processing the osdmap if an overflow occurred. Therefore,
osdmaps/messages containing large values for len that result in a
multiplication overflow are treated as invalid.

[ idryomov: rename new_state_len -> new_state_item_size, formatting ]

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-68158?


## How do I fix CVE-2026-68158?

Apply the vendor's patch.

## Is CVE-2026-68158 being exploited?

There is no known exploitation of CVE-2026-68158 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68158 and fix it if it is affected.

What it is: CVE-2026-68158 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-2026-68158 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-2026-68158/ (Markdown: https://insights.sbomify.com/CVE-2026-68158/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68158
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68158
- OSV: https://osv.dev/vulnerability/CVE-2026-68158

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68158/
Summaries are generated and may contain mistakes; the official description above is the record.