PT-2026-64587 · Linux · Linux

CVE-2026-64366

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Published

2026-07-25

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Updated

2026-07-25

None

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In the Linux kernel, the following vulnerability has been resolved:
HID: wacom: fix slab-out-of-bounds write in wacom wac queue insert
wacom wac queue insert() calls kfifo skip() in a loop when the kfifo doesn't have enough space for the incoming report. If the kfifo is empty, kfifo skip() reads stale data left in the kmalloc'd buffer via kfifo peek n() and interprets it as a record length, advancing fifo->out by that garbage value. This corrupts the internal kfifo state, causing kfifo unused() to return a value much larger than the actual buffer size, which bypasses kfifo in r()'s guard:
if (len + recsize > kfifo unused(fifo)) return 0;
kfifo copy in() then performs an out-of-bounds memcpy, writing up to 3842 bytes past the 256-byte buffer.
Add a !kfifo is empty() condition to the while loop so kfifo skip() is never called on an empty fifo, and check the return value of kfifo in() to reject reports that are too large for the fifo.
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Related Identifiers

CVE-2026-64366

Affected Products

Linux