# CVE-2023-52636: libceph: just wait for more data to be available on the socket

> A logic error in the Linux kernel's Ceph client can cause a denial of service by misinterpreting network data during sparse reads.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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:** 2 Apr 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2023-52636, DEBIAN-CVE-2023-52636, GHSA-fqg2-664v-fx4j, UBUNTU-CVE-2023-52636

## What is CVE-2023-52636?

CVE-2023-52636 is a high-severity denial of service vulnerability in Linux kernel, published on 2 Apr 2024. 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: just wait for more data to be available on the socket

A short read may occur while reading the message footer from the
socket.  Later, when the socket is ready for another read, the
messenger invokes all read_partial_*() handlers, including
read_partial_sparse_msg_data().  The expectation is that
read_partial_sparse_msg_data() would bail, allowing the messenger to
invoke read_partial() for the footer and pick up where it left off.

However read_partial_sparse_msg_data() violates that and ends up
calling into the state machine in the OSD client.  The sparse-read
state machine assumes that it's a new op and interprets some piece of
the footer as the sparse-read header and returns bogus extents/data
length, etc.

To determine whether read_partial_sparse_msg_data() should bail, let's
reuse cursor->total_resid.  Because once it reaches to zero that means
all the extents and data have been successfully received in last read,
else it could break out when partially reading any of the extents and
data.  And then osd_sparse_read() could continue where it left off.

[ idryomov: changelog ]

## Which versions are affected by CVE-2023-52636?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-52636?

Apply the vendor's patch.

## Is CVE-2023-52636 being exploited?

There is no known exploitation of CVE-2023-52636 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-2023-52636 and fix it if it is affected.

What it is: CVE-2023-52636 is a high-severity denial of service vulnerability in Linux kernel, published on 2 Apr 2024. 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-2023-52636 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-2023-52636/ (Markdown: https://insights.sbomify.com/CVE-2023-52636/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-52636
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-52636
- OSV: https://osv.dev/vulnerability/CVE-2023-52636

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-52636/
Summaries are generated and may contain mistakes; the official description above is the record.