Description
In the Linux kernel, the following vulnerability has been resolved:

net: qualcomm: rmnet: restore skb->dev on deaggregated frames

rmnet_map_deaggregate() allocates each sub-frame with alloc_skb() and
leaves skb->dev NULL. __rmnet_map_ingress_handler() assigns
skb->dev = ep->egress_dev only on the data path, but a MAP command frame
is dispatched to rmnet_map_command() before that, so rmnet_map_send_ack()
runs netif_tx_lock(skb->dev) on a NULL device. An unprivileged user
reaches this by unsharing a user+net namespace, creating an rmnet link
over a tap device with INGRESS_DEAGGREGATION and INGRESS_MAP_COMMANDS,
and writing an aggregated frame carrying a flow-control command to the
tap fd.

Restore the assignment dropped by 378e25357ac7, so every skb leaving
rmnet_map_deaggregate() has a valid device.

BUG: KASAN: null-ptr-deref in _raw_spin_lock (kernel/locking/spinlock.c:158)
Write of size 4 at addr 00000000000004b4 by task exploit/144
Call Trace:
_raw_spin_lock (kernel/locking/spinlock.c:158)
netif_tx_lock (net/sched/sch_generic.c:497)
rmnet_map_command (drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c:67)
rmnet_rx_handler (drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c:125)
__netif_receive_skb_core.constprop.0 (net/core/dev.c:6103)
...
__netif_receive_skb_one_core (net/core/dev.c:6214)
netif_receive_skb (net/core/dev.c:6474)
tun_get_user (drivers/net/tun.c:1966)
tun_chr_write_iter (drivers/net/tun.c:2012)
vfs_write (fs/read_write.c:687)
ksys_write (fs/read_write.c:739)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Kernel panic - not syncing: Fatal exception in interrupt
Published: 2026-09-16
Score: n/a
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Wed, 16 Sep 2026 14:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-476

Wed, 16 Sep 2026 09:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net: qualcomm: rmnet: restore skb->dev on deaggregated frames rmnet_map_deaggregate() allocates each sub-frame with alloc_skb() and leaves skb->dev NULL. __rmnet_map_ingress_handler() assigns skb->dev = ep->egress_dev only on the data path, but a MAP command frame is dispatched to rmnet_map_command() before that, so rmnet_map_send_ack() runs netif_tx_lock(skb->dev) on a NULL device. An unprivileged user reaches this by unsharing a user+net namespace, creating an rmnet link over a tap device with INGRESS_DEAGGREGATION and INGRESS_MAP_COMMANDS, and writing an aggregated frame carrying a flow-control command to the tap fd. Restore the assignment dropped by 378e25357ac7, so every skb leaving rmnet_map_deaggregate() has a valid device. BUG: KASAN: null-ptr-deref in _raw_spin_lock (kernel/locking/spinlock.c:158) Write of size 4 at addr 00000000000004b4 by task exploit/144 Call Trace: _raw_spin_lock (kernel/locking/spinlock.c:158) netif_tx_lock (net/sched/sch_generic.c:497) rmnet_map_command (drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c:67) rmnet_rx_handler (drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c:125) __netif_receive_skb_core.constprop.0 (net/core/dev.c:6103) ... __netif_receive_skb_one_core (net/core/dev.c:6214) netif_receive_skb (net/core/dev.c:6474) tun_get_user (drivers/net/tun.c:1966) tun_chr_write_iter (drivers/net/tun.c:2012) vfs_write (fs/read_write.c:687) ksys_write (fs/read_write.c:739) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Kernel panic - not syncing: Fatal exception in interrupt
Title net: qualcomm: rmnet: restore skb->dev on deaggregated frames
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-16T08:48:19.760Z

Reserved: 2026-09-11T19:38:34.765Z

Link: CVE-2026-89780

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-16T09:17:08.520

Modified: 2026-09-16T09:17:08.520

Link: CVE-2026-89780

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-16T14:30:10Z

Weaknesses