CVE-2026-98567net: xps: reject an out of range traffic class

In the Linux kernel, the following vulnerability has been resolved: net: xps: reject an out of range traffic class Only the entries below dev->num_tc are valid in dev->tc_to_txq[], and dev->prio_tc_map[] may only name classes below it. netdev_set_num_tc() lowers dev->num_tc without touching either array. netdev_txq_to_tc() walks all TC_MAX_QUEUE slots and netdev_get_prio_tc_map() returns the entry as it stands, so a leftover entry is handed out as a traffic class >= dev->num_tc. Taking that class from netdev_txq_to_tc(), __netif_set_xps_queue() rejects only a negative one and indexes an XPS map sized for dev->num_tc classes: tci = j * num_tc + tc; RCU_INIT_POINTER(new_dev_maps->attr_map[tci], map); attr_map[] holds nr_ids * num_tc entries and j runs over the ids named in the mask, so a class that is not below num_tc pushes tci past the end of the map for the last ids and the store overruns it. Any caller that lowers num_tc leaves such entries behind, and mqprio_destroy() tears down with netdev_set_num_tc(dev, 0) rather than netdev_reset_tc(). After mqprio with 8 classes then 1, tc_to_txq[1..7] still describe txq 1..7. The splat is from an XPS write to txq 2 on a veth with 8 rx queues: attr_map[] has 8 * 1 entries, tci = j + 2, and j == 6 stores one past the end of the 88-byte map: BUG: KASAN: slab-out-of-bounds in __netif_set_xps_queue (net/core/dev.c:2954) Write of size 8 at addr ffff88813016bc58 by task xps_oob/634 __netif_set_xps_queue (net/core/dev.c:2954) xps_rxqs_store (net/core/net-sysfs.c:1880) netdev_queue_attr_store (net/core/net-sysfs.c:1390) Allocated by task 634: __kmalloc_noprof (mm/slub.c:5439) __netif_set_xps_queue (net/core/dev.c:2937) The buggy address is located 0 bytes to the right of allocated 88-byte region [ffff88813016bc00, ffff88813016bc58) Reject a class the map has no room for.

CVSS

Not yet scored

Weakness (CWE)

Not given

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Linux

NVD analysis

Received

Record last updated

Oct 18, 2026

First seen by InfoSec Signals

Oct 18, 2026

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