# CVE-2026-93106: crash_dump: release keyring reference at the correct time

CVE-2026-93106 is fixed in linux on 1 platform by DEBIAN-CVE-2026-93106 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-93106
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0021
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 17, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-93106

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-93106](https://patchblox.com/security/data/fix/linux/debian-cve-2026-93106.md) | Sep 23, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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