CVE-2026-99222
Received Received - Intake

Use-After-Free in Linux Kernel Key Management

Publication date: 2026-11-02

Last updated on: 2026-11-02

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: keys: Protect the read method check against type removal keyctl_read_key() checks key->type->read without holding key->sem. A reference keeps the key alive, but does not pin the module containing its type. A surviving RxRPC key can therefore be read while AF_RXRPC is being unloaded: KEYCTL_READ task Module unload and key GC ---------------- ------------------------ lookup_user_key() permission / possession checks load key->type af_rxrpc_exit() unregister_key_type() GC: down_write(key->sem) GC: retype to key_type_dead GC: up_write(key->sem) unregister_key_type() returns free_module() read saved type's read member The final access can read freed module storage. The read invocation in __keyctl_read_key() is already protected by key->sem, but the earlier method check is outside that critical section. Move the method check into __keyctl_read_key(), after key_validate() and under its existing read hold on key->sem. The check and invocation then use the same protected type for length queries and every read retry. The GC cannot retype the key until the semaphore is released, and type unregistration waits for that GC pass before the module can be freed. Return -EOPNOTSUPP when validation succeeds and the type has no read method. A temporary buffer may now be allocated before this result; allocation and copying to userspace remain outside the semaphore.

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Meta Information

Published
2026-11-02
Last Modified
2026-11-02
Generated
2026-11-02
AI Q&A
2026-11-02
EPSS Evaluated
N/A
NVD
CVE-2026-99222

Affected Vendors & Products

Showing 17 associated CPEs
Vendor Product Version / Range
Linux Linux d3ec10aa95819bff18a0d936b18884c7816d0914
Linux Linux d3ec10aa95819bff18a0d936b18884c7816d0914
Linux Linux d3ec10aa95819bff18a0d936b18884c7816d0914
Linux Linux d3ec10aa95819bff18a0d936b18884c7816d0914
Linux Linux d3ec10aa95819bff18a0d936b18884c7816d0914
Linux Linux d3ec10aa95819bff18a0d936b18884c7816d0914
Linux Linux d3ec10aa95819bff18a0d936b18884c7816d0914
Linux Linux d3ec10aa95819bff18a0d936b18884c7816d0914
Linux Linux 7fa67aa30509ad0da72ac0f757aa76e53c0ea3de
Linux Linux 18779eac17b5df9dff57138d07631573553a41d4
Linux Linux f1afcf9488fc45765e20e2047d3b776981900e0b
Linux Linux 212d3adb1af4e34acb158d6c6def370016a1011d
Linux Linux 4.14.177
Linux Linux 4.19.118
Linux Linux 5.4.35
Linux Linux 5.6.7
Linux Linux 5.7

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a race condition in the key management subsystem. The issue occurs when the keyctl_read_key() function checks the key type's read method without holding the key's semaphore lock. This allows a key to be accessed while its associated module (AF_RXRPC) is being unloaded, potentially leading to reading freed memory.

Detection Guidance

This vulnerability is specific to the Linux kernel and does not have a direct network detection method. Detection involves checking the kernel version and verifying if the vulnerable code path exists. Use commands like 'uname -a' to check the kernel version and 'dmesg' or 'journalctl' to look for related errors during module unloading or key operations.

Impact Analysis

An attacker could exploit this to cause a system crash or execute arbitrary code with kernel privileges. This could lead to unauthorized data access, privilege escalation, or denial of service on affected Linux systems.

Compliance Impact

This vulnerability involves a race condition in the Linux kernel's key management subsystem that could allow unauthorized access to freed memory during key type unloading. While it does not directly impact data protection standards like GDPR or HIPAA, it could potentially lead to information disclosure if exploited, which may violate confidentiality requirements under these regulations.

Mitigation Strategies

Apply the latest kernel patches or updates that address this issue. If patches are unavailable, consider disabling the AF_RXRPC module if not in use. Monitor kernel logs for unusual activity related to key operations or module unloading.

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