CVE-2026-64366
Full vulnerability record from the local CVENow database.
Description
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.
Severity
HIGH
CVSS score
8.8
(v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-07-25 10:17:19.403000
Last modified
2026-10-19 21:17:33.120000
View original CVE JSON
{
"id": "CVE-2026-64366",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-07-25T10:17:19.403",
"lastModified": "2026-10-19T21:17:33.120",
"vulnStatus": "Modified",
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{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nHID: wacom: fix slab-out-of-bounds write in wacom_wac_queue_insert\n\nwacom_wac_queue_insert() calls kfifo_skip() in a loop when the kfifo\ndoesn't have enough space for the incoming report. If the kfifo is\nempty, kfifo_skip() reads stale data left in the kmalloc'd buffer\nvia __kfifo_peek_n() and interprets it as a record length, advancing\nfifo->out by that garbage value. This corrupts the internal kfifo\nstate, causing kfifo_unused() to return a value much larger than the\nactual buffer size, which bypasses __kfifo_in_r()'s guard:\n\n if (len + recsize > kfifo_unused(fifo))\n return 0;\n\nkfifo_copy_in() then performs an out-of-bounds memcpy, writing up to\n3842 bytes past the 256-byte buffer.\n\nAdd a !kfifo_is_empty() condition to the while loop so kfifo_skip()\nis never called on an empty fifo, and check the return value of\nkfifo_in() to reject reports that are too large for the fifo."
}
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