# CVE-2026-72103: dm: avoid leaking the caller's thread keyring via the table device file

> An attacker with CAP_SYS_ADMIN can recover LUKS volume keys from RAM after suspend due to a kernel bug leaking the keyring reference.

- **Severity:** High 7.3 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L`)
- **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:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-72103, DEBIAN-CVE-2026-72103, GHSA-mq86-3x2m-mwpc, UBUNTU-CVE-2026-72103

## What is CVE-2026-72103?

CVE-2026-72103 is a high-severity 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: avoid leaking the caller's thread keyring via the table device file

The refactoring in commit a28d893eb327 ("md: port block device access to file")
accidentally causes the caller's thread keyring to be kept alive long
beyond the caller's lifetime.

As a result, "cryptsetup luksSuspend" silently fails to wipe the
LUKS volume key from memory.

In detail: "cryptsetup luksOpen" uses its supposedly ephemeral thread
keyring to pass the volume key to the kernel. dm-crypt's
crypt_set_keyring_key() copies the key material into its own
crypt_config structure and then drops its own reference to the key in
the keyring with key_put().

With this fix, restoring pre-v6.9 behavior, the copy in the thread
keyring is then promptly garbage collected, such that exactly one copy
of the volume key remains. This single copy is correctly wiped from
memory on "cryptsetup luksSuspend".

Without this fix, the thread keyring and the volume key in it remains.
This second copy is only freed on "luksClose". "luksSuspend" neither
knows about this copy nor has any way to remove it, so the key remains
recoverable from RAM after a suspend that is documented to have wiped it.

This fix should not introduce new security problems, as the code is
anyway gated by CAP_SYS_ADMIN. The device-mapper core, not the calling
task, is the legitimate owner of this long-lived file.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-72103?


## How do I fix CVE-2026-72103?

Apply the vendor's patch.

## Is CVE-2026-72103 being exploited?

There is no known exploitation of CVE-2026-72103 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72103 and fix it if it is affected.

What it is: CVE-2026-72103 is a high-severity 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-2026-72103 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-2026-72103/ (Markdown: https://insights.sbomify.com/CVE-2026-72103/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72103
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72103
- OSV: https://osv.dev/vulnerability/CVE-2026-72103

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72103/
Summaries are generated and may contain mistakes; the official description above is the record.