# CVE-2026-72104: dm-pcache: reject option groups without values

> A local attacker can cause a kernel crash by providing malformed device-mapper pcache table arguments, leading to a denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-72104, DEBIAN-CVE-2026-72104, GHSA-3wp6-4r9h-frm7, UBUNTU-CVE-2026-72104

## What is CVE-2026-72104?

CVE-2026-72104 is a vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

dm-pcache: reject option groups without values

The pcache target parses optional arguments as name/value pairs.  A
table that advertises one optional argument and supplies only a
recognized option name, for example "cache_mode", reaches
parse_cache_opts() with argc == 1.  The parser consumes the name,
decrements argc to zero, then calls dm_shift_arg() again for the value.
dm_shift_arg() returns NULL when no arguments remain, and the following
strcmp() dereferences that NULL pointer.

Check that each recognized option has a value before consuming it.  This
keeps valid "cache_mode writeback" and "data_crc true/false" tables
unchanged while making malformed tables fail during target construction
with a precise missing-value error.

## Which versions are affected by CVE-2026-72104?


## How do I fix CVE-2026-72104?

Apply the vendor's patch.

## Is CVE-2026-72104 being exploited?

There is no known exploitation of CVE-2026-72104 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72104 and fix it if it is affected.

What it is: CVE-2026-72104 is a vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-72104 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-2026-72104/ (Markdown: https://insights.sbomify.com/CVE-2026-72104/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72104
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72104
- OSV: https://osv.dev/vulnerability/CVE-2026-72104

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72104/
Summaries are generated and may contain mistakes; the official description above is the record.