CVE-2026-45977
fbnic: close fw_log race between users and teardown
Description
In the Linux kernel, the following vulnerability has been resolved: fbnic: close fw_log race between users and teardown Fixes a theoretical race on fw_log between the teardown path and fw_log write functions. fw_log is written inside fbnic_fw_log_write() and can be reached from the mailbox handler fbnic_fw_msix_intr(), but fw_log is freed before IRQ/MBX teardown during cleanup, resulting in a potential data race of dereferencing a freed/null variable. Possible Interleaving Scenario: CPU0: fbnic_fw_msix_intr() // Entry fbnic_fw_log_write() if (fbnic_fw_log_ready()) // true ... preempt ... CPU1: fbnic_remove() // Entry fbnic_fw_log_free() vfree(log->data_start); log->data_start = NULL; CPU0: continues, walks log->entries or writes to log->data_start The initialization also has an incorrect order problem, as the fw_log is currently allocated after MBX setup during initialization. Fix the problems by adjusting the synchronization order to put initialization in place before the mailbox is enabled, and not cleared until after the mailbox has been disabled.
INFO
Published Date :
May 27, 2026, 2:17 p.m.
Last Modified :
May 27, 2026, 2:48 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Ensure log allocation precedes mailbox setup.
- Disable mailbox before clearing log.
- Update synchronization order for initialization.
- Modify teardown sequence for cleanup.
References to Advisories, Solutions, and Tools
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CVE-2026-45977.
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associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-45977
weaknesses.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 27, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: fbnic: close fw_log race between users and teardown Fixes a theoretical race on fw_log between the teardown path and fw_log write functions. fw_log is written inside fbnic_fw_log_write() and can be reached from the mailbox handler fbnic_fw_msix_intr(), but fw_log is freed before IRQ/MBX teardown during cleanup, resulting in a potential data race of dereferencing a freed/null variable. Possible Interleaving Scenario: CPU0: fbnic_fw_msix_intr() // Entry fbnic_fw_log_write() if (fbnic_fw_log_ready()) // true ... preempt ... CPU1: fbnic_remove() // Entry fbnic_fw_log_free() vfree(log->data_start); log->data_start = NULL; CPU0: continues, walks log->entries or writes to log->data_start The initialization also has an incorrect order problem, as the fw_log is currently allocated after MBX setup during initialization. Fix the problems by adjusting the synchronization order to put initialization in place before the mailbox is enabled, and not cleared until after the mailbox has been disabled. Added Reference https://git.kernel.org/stable/c/223cfef4812bdfa5ac5c1aa761cdba03cfe2c9cd Added Reference https://git.kernel.org/stable/c/5f10ab3643c58a22fbaee92c4701b00fcb4a465d Added Reference https://git.kernel.org/stable/c/ee5492fd88cfc079c19fbeac78e9e53b7f6c04f3