CVE-2026-23153: 
Linux Kernel vulnerability analysis and mitigation

CVE-2026-23153 is a race condition vulnerability in the Linux kernel's firewire core subsystem. The transaction list is enumerated without acquiring the card lock when processing Asynchronous Response (AR) events, creating a race condition when Asynchronous Transmit (AT) request completion events are processed concurrently. It affects Linux kernel versions 6.18 through 6.18.8 and 6.19-rc1 through 6.19-rc7. The vulnerability carries a CVSS v3.1 base score of 4.7 (Medium) (Feedly).

The root cause is improper synchronization (CWE-362: Race Condition) in the firewire core subsystem's transaction handling. Specifically, the timer start for split transaction expiration is not placed within the card lock scope, and jiffies values are read from the card structure before the lock is acquired. This allows a local attacker with low privileges to trigger concurrent AR response and AT request completion processing, leading to unsynchronized access to the shared transaction list. The fix places the timer start operation inside the lock scope to ensure proper synchronization (Feedly, Kernel Patch 1, Kernel Patch 2).

Successful exploitation allows a local attacker with low privileges to cause a denial of service condition, potentially crashing the kernel or hanging system processes through improper synchronization of firewire transaction handling. The impact is limited to availability (no confidentiality or integrity impact), and exploitation requires local access and high attack complexity due to the timing-dependent nature of the race condition. The affected scope is unchanged, meaning the impact is confined to the vulnerable system (Feedly).

Patches are available via two upstream kernel commits: 20e01bba2ae4898ce65cdcacd1bd6bec5111abd9 and b038874e31fc3caa0b0d5abd259dd54b918ad4a1, targeting kernel versions 6.18.9+ and the 6.19 stable release. Affected systems running Linux kernel 6.18 through 6.18.8 or 6.19-rc1 through 6.19-rc7 should be updated to the fixed versions as soon as possible. As a temporary workaround, administrators can restrict local user privileges and disable the firewire subsystem if it is not required for operations (Feedly, Kernel Patch 1, Kernel Patch 2).