CVE-2026-72103

Received Received - Intake

Memory Leak in Linux Kernel dm-crypt

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

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.

CVSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-17

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-72103

EUVD

EUVD-2026-59061

Affected Vendors & Products

Vendor	Product	Version / Range
cryptsetup	cryptsetup	From 6.9 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a flaw in the device-mapper (dm) subsystem where the caller's thread keyring is accidentally kept alive beyond its intended lifetime due to refactoring in commit a28d893eb327. This causes cryptsetup's luksSuspend command to fail silently in wiping the LUKS volume key from memory, leaving a second copy of the key recoverable from RAM after a suspend operation.

Detection Guidance

This vulnerability is specific to the Linux kernel's device-mapper (dm) subsystem and cryptsetup. Detection requires checking kernel version and cryptsetup behavior. Use 'uname -r' to check kernel version and 'cryptsetup --version' to verify cryptsetup version. Monitor for failed 'luksSuspend' operations or unexpected key retention in memory.

Impact Analysis

If you use LUKS-encrypted volumes with cryptsetup on a vulnerable Linux kernel, an attacker with access to your system's RAM after a suspend operation could potentially recover the encryption key. This could lead to unauthorized access to your encrypted data.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as described in the provided context. The issue involves memory management in the Linux kernel's device-mapper subsystem, specifically related to keyring handling and cryptsetup operations. There is no indication that this vulnerability leads to unauthorized data access, data breaches, or non-compliance with regulatory requirements.

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix. If updating is not immediately possible, avoid using 'cryptsetup luksSuspend' and ensure sensitive keys are manually cleared from memory after use. Restrict CAP_SYS_ADMIN capabilities to trusted users.

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