# CVE-2026-68131: rbd: Reset positive result codes to zero in object map update path

> A corrupted reply in the RBD object map update path triggers a kernel assertion, causing a denial of service.

- **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:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-68131, DEBIAN-CVE-2026-68131, GHSA-rwc8-9546-9gw5, UBUNTU-CVE-2026-68131

## What is CVE-2026-68131?

CVE-2026-68131 is a high-severity denial of service 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:

rbd: Reset positive result codes to zero in object map update path

In a reply message to an RBD request, a positive result code indicates
a data payload, which is not allowed for writes. While
rbd_osd_req_callback() already resets a positive result code for writes
to zero, rbd_object_map_callback() does not. This allows a corrupted
reply to an object map update to trigger the rbd_assert(*result < 0) in
__rbd_obj_handle_request(). This happens, because
rbd_object_map_callback() calls rbd_obj_handle_request() ->
__rbd_obj_handle_request() and passes this positive result code. From
__rbd_obj_handle_request(), rbd_obj_advance_write() is called, which
leaves the positive result code unchanged and returns true. Therefore,
the if(done && *result) branch is executed in __rbd_obj_handle_request()
and the assertion triggers.

This patch fixes the issue by adjusting the logic in the
rbd_object_map_callback() path. A positive result code for an object map
update is now reset to zero (similar to rbd_osd_req_callback()), and the
message is subsequently handled the same way as if the result code was
zero from the beginning. Additionally, a WARN_ON_ONCE() is added for
this case.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-68131?


## How do I fix CVE-2026-68131?

Apply the vendor's patch.

## Is CVE-2026-68131 being exploited?

There is no known exploitation of CVE-2026-68131 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68131 and fix it if it is affected.

What it is: CVE-2026-68131 is a high-severity denial of service 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-2026-68131 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-2026-68131/ (Markdown: https://insights.sbomify.com/CVE-2026-68131/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68131
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68131
- OSV: https://osv.dev/vulnerability/CVE-2026-68131

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68131/
Summaries are generated and may contain mistakes; the official description above is the record.