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

crash_dump: release keyring reference at the correct time

restore_dm_crypt_keys_to_thread_keyring() gets a reference to the user
keyring before restoring the saved dm-crypt keys.

The same keyring reference is then passed to add_key_to_keyring() for each
saved key, but add_key_to_keyring() drops that reference on every call.
This is only balanced when exactly one key is restored. With multiple
keys, the keyring reference is dropped too many times and may trigger a
refcount underflow or use-after-free.

When more than five keys are restored, a refcount underflow/use-after-free
warning can be triggered.

The early error paths after lookup_user_key() also return without dropping
the keyring reference.

Keep ownership of the keyring reference in
restore_dm_crypt_keys_to_thread_keyring(), drop it once on all exit paths,
and make add_key_to_keyring() only use the reference without consuming it.
Published: 2026-09-17
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Thu, 17 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: crash_dump: release keyring reference at the correct time restore_dm_crypt_keys_to_thread_keyring() gets a reference to the user keyring before restoring the saved dm-crypt keys. The same keyring reference is then passed to add_key_to_keyring() for each saved key, but add_key_to_keyring() drops that reference on every call. This is only balanced when exactly one key is restored. With multiple keys, the keyring reference is dropped too many times and may trigger a refcount underflow or use-after-free. When more than five keys are restored, a refcount underflow/use-after-free warning can be triggered. The early error paths after lookup_user_key() also return without dropping the keyring reference. Keep ownership of the keyring reference in restore_dm_crypt_keys_to_thread_keyring(), drop it once on all exit paths, and make add_key_to_keyring() only use the reference without consuming it.
Title crash_dump: release keyring reference at the correct time
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-17T16:11:17.136Z

Reserved: 2026-09-17T16:02:15.085Z

Link: CVE-2026-93106

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.