CVE-2026-89780 is a vulnerability in Linux Kernel
Published on September 16, 2026
net: qualcomm: rmnet: restore skb->dev on deaggregated frames
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
Products Associated with CVE-2026-89780
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Affected Versions
Linux:- Version 378e25357ac78ad02fbc98bec9b4e3baaa916c5c and below 5aaa7409c1b4ca4c60d66e2afa99703bf4eb7ddd is affected.
- Version 378e25357ac78ad02fbc98bec9b4e3baaa916c5c and below 9b78ab84ddf97c06a8567edb62b6c0fd582f9a62 is affected.
- Version 378e25357ac78ad02fbc98bec9b4e3baaa916c5c and below 9d18c6c6cd1666b2cb7915cad052e22abf520997 is affected.
- Version 378e25357ac78ad02fbc98bec9b4e3baaa916c5c and below 4bcef54e4a3355a62d9ad90729fe563435ec76c3 is affected.
- Version 378e25357ac78ad02fbc98bec9b4e3baaa916c5c and below b14c22c31d9e30f38ea1693ac06d318f32258f5d is affected.
- Version 378e25357ac78ad02fbc98bec9b4e3baaa916c5c and below 7abe769e72c792e5f9eb273813eb3ecd8389854c is affected.
- Version 378e25357ac78ad02fbc98bec9b4e3baaa916c5c and below 200460a0793dc6af97d3b36d92ac245350ac26fc is affected.
- Version 378e25357ac78ad02fbc98bec9b4e3baaa916c5c and below a66734a1c5e36525ea07e9f4547fddc51e916de3 is affected.
- Version 4.17 is affected.
- Before 4.17 is unaffected.
- Version 5.10.270, <= 5.10.* is unaffected.
- Version 5.15.221, <= 5.15.* is unaffected.
- Version 6.1.188, <= 6.1.* is unaffected.
- Version 6.6.157, <= 6.6.* is unaffected.
- Version 6.12.110, <= 6.12.* is unaffected.
- Version 6.18.52, <= 6.18.* is unaffected.
- Version 7.2.6, <= 7.2.* is unaffected.
- Version 7.3-rc1, <= * is unaffected.