Vulnerability Details CVE-2026-53163
In the Linux kernel, the following vulnerability has been resolved:
locking/rtmutex: Skip remove_waiter() when waiter is not enqueued
syzbot triggered the following splat in remove_waiter() via
FUTEX_CMP_REQUEUE_PI:
KASAN: null-ptr-deref in range [0x0000000000000a88-0x0000000000000a8f]
class_raw_spinlock_constructor
remove_waiter+0x159/0x1200 kernel/locking/rtmutex.c:1561
rt_mutex_start_proxy_lock+0x103/0x120
futex_requeue+0x10e4/0x20d0
__x64_sys_futex+0x34f/0x4d0
task_blocks_on_rt_mutex() does not arm the waiter upon deadlock detection,
leaving waiter->task nil, where 3bfdc63936dd ("rtmutex: Use waiter::task instead
of current in remove_waiter()") made this fatal.
Furthermore, rt_mutex_start_proxy_lock() should not be calling into remove_waiter()
upon a successfully grabbing the rtmutex. 1a1fb985f2e2 ("futex: Handle early deadlock
return correctly"), moved the remove_waiter() out of __rt_mutex_start_proxy_lock()
(where 'ret' was only ever 0 or < 0) into the wrapper. Tighten this check to
account for try_to_take_rt_mutex().
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 2.4%
CVSS Severity
CVSS v3 Score 5.5
Products affected by CVE-2026-53163
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cpe:2.3:o:linux:linux_kernel:6.1.175
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cpe:2.3:o:linux:linux_kernel:6.1.176
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cpe:2.3:o:linux:linux_kernel:6.12.86
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cpe:2.3:o:linux:linux_kernel:6.12.87
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cpe:2.3:o:linux:linux_kernel:6.12.88
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cpe:2.3:o:linux:linux_kernel:6.12.89
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cpe:2.3:o:linux:linux_kernel:6.12.90
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cpe:2.3:o:linux:linux_kernel:6.12.91
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cpe:2.3:o:linux:linux_kernel:6.12.92
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cpe:2.3:o:linux:linux_kernel:6.12.93
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cpe:2.3:o:linux:linux_kernel:6.12.94
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cpe:2.3:o:linux:linux_kernel:6.18.27
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cpe:2.3:o:linux:linux_kernel:6.18.28
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cpe:2.3:o:linux:linux_kernel:6.18.29
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cpe:2.3:o:linux:linux_kernel:6.18.30
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cpe:2.3:o:linux:linux_kernel:6.18.31
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cpe:2.3:o:linux:linux_kernel:6.18.32
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cpe:2.3:o:linux:linux_kernel:6.18.33
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cpe:2.3:o:linux:linux_kernel:6.18.34
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cpe:2.3:o:linux:linux_kernel:6.18.35
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cpe:2.3:o:linux:linux_kernel:6.6.140
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cpe:2.3:o:linux:linux_kernel:6.6.141
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cpe:2.3:o:linux:linux_kernel:6.6.142
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cpe:2.3:o:linux:linux_kernel:6.6.143
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cpe:2.3:o:linux:linux_kernel:7.0.10
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cpe:2.3:o:linux:linux_kernel:7.0.11
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cpe:2.3:o:linux:linux_kernel:7.0.12
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cpe:2.3:o:linux:linux_kernel:7.0.4
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cpe:2.3:o:linux:linux_kernel:7.0.5
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cpe:2.3:o:linux:linux_kernel:7.0.6
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cpe:2.3:o:linux:linux_kernel:7.0.7
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cpe:2.3:o:linux:linux_kernel:7.0.8
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cpe:2.3:o:linux:linux_kernel:7.0.9
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cpe:2.3:o:linux:linux_kernel:7.1