# CVE-2026-52958: libceph: Fix potential out-of-bounds access in osdmap_decode()

> A corrupted Ceph OSD map message can trigger an out-of-bounds memory access in the Linux kernel, potentially leading to system crashes or arbitrary code execution.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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:** 24 Jun 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-52958, DEBIAN-CVE-2026-52958, GHSA-xhq7-864q-xxj8, ROOT-OS-DEBIAN-11-CVE-2026-52958, ROOT-OS-DEBIAN-12-CVE-2026-52958, ROOT-OS-UBUNTU-2204-CVE-2026-52958, ROOT-OS-UBUNTU-2404-CVE-2026-52958, UBUNTU-CVE-2026-52958

## What is CVE-2026-52958?

CVE-2026-52958 is a critical memory corruption vulnerability in Linux kernel, published on 24 Jun 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 potential out-of-bounds access in osdmap_decode()

When decoding osd_state and osd_weight from an incoming osdmap in
osdmap_decode(), both are decoded for each osd, i.e., map->max_osd
times. The ceph_decode_need() check only accounts for
sizeof(*map->osd_weight) once. This can potentially result in an
out-of-bounds memory access if the incoming message is corrupted such
that the max_osd value exceeds the actual content of the osdmap message.

This patch fixes the issue by changing the corresponding part in the
ceph_decode_need() check to account for
map->max_osd*sizeof(*map->osd_weight).

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-52958?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-52958?

Apply the vendor's patch.

## Is CVE-2026-52958 being exploited?

There is no known exploitation of CVE-2026-52958 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-2026-52958 and fix it if it is affected.

What it is: CVE-2026-52958 is a critical memory corruption vulnerability in Linux kernel, published on 24 Jun 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-2026-52958 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-2026-52958/ (Markdown: https://insights.sbomify.com/CVE-2026-52958/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-52958
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-52958
- OSV: https://osv.dev/vulnerability/CVE-2026-52958

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-52958/
Summaries are generated and may contain mistakes; the official description above is the record.