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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-23277

net/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit teql_master_xmit() calls netdev_start_xmit(skb, slave) to transmit through slave devices, but does not update skb->dev to the slave device beforehand. When a gretap tunnel is a TEQL slave, the transmit path reaches iptunnel_xmit() which saves dev = skb->dev (still pointing to teql0 master) and later calls iptunnel_xmit_stats(dev, pkt_len). This function does: get_cpu_ptr(dev->tstats) Since teql_master_setup() does not set dev->pcpu_stat_type to NETDEV_PCPU_STAT_TSTATS, the core network stack never allocates tstats for teql0, so dev->tstats is NULL. get_cpu_ptr(NULL) computes NULL + __per_cpu_offset[cpu], resulting in a page fault. BUG: unable to handle page fault for address: ffff8880e6659018 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 68bc067 P4D 68bc067 PUD 0 Oops: Oops: 0002 [#1] SMP KASAN PTI RIP: 0010:iptunnel_xmit (./include/net/ip_tunnels.h:664 net/ipv4/ip_tunnel_core.c:89) Call Trace: <TASK> ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847) __gre_xmit (net/ipv4/ip_gre.c:478) gre_tap_xmit (net/ipv4/ip_gre.c:779) teql_master_xmit (net/sched/sch_teql.c:319) dev_hard_start_xmit (net/core/dev.c:3887) sch_direct_xmit (net/sched/sch_generic.c:347) __dev_queue_xmit (net/core/dev.c:4802) neigh_direct_output (net/core/neighbour.c:1660) ip_finish_output2 (net/ipv4/ip_output.c:237) __ip_finish_output.part.0 (net/ipv4/ip_output.c:315) ip_mc_output (net/ipv4/ip_output.c:369) ip_send_skb (net/ipv4/ip_output.c:1508) udp_send_skb (net/ipv4/udp.c:1195) udp_sendmsg (net/ipv4/udp.c:1485) inet_sendmsg (net/ipv4/af_inet.c:859) __sys_sendto (net/socket.c:2206) Fix this by setting skb->dev = slave before calling netdev_start_xmit(), so that tunnel xmit functions see the correct slave device with properly allocated tstats.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 039f50629b7f860f36644ed1f34b27da9aa62f43 to < 383493b9940e3d1b5517424081b3e072e20ec43caffected
  • 039f50629b7f860f36644ed1f34b27da9aa62f43 to < 6b1f563d670162e188a0f2aec39c24b67b106e17affected
  • 039f50629b7f860f36644ed1f34b27da9aa62f43 to < 57c153249143333bbf4ecf927bdf8aa2696ee397affected
  • 039f50629b7f860f36644ed1f34b27da9aa62f43 to < 59b06d8b9bdb6b64b3c534c18da68bce5ccd31beaffected
  • 039f50629b7f860f36644ed1f34b27da9aa62f43 to < 81a43e8005366f16e629d8c95dfe05beaa8d36a7affected
  • 039f50629b7f860f36644ed1f34b27da9aa62f43 to < 0bad9c86edd22dec4df83c2b29872d66fd8a2ff4affected
  • 039f50629b7f860f36644ed1f34b27da9aa62f43 to < 21ea283c2750c8307aa35ee832b0951cc993c27daffected
  • 039f50629b7f860f36644ed1f34b27da9aa62f43 to < 0cc0c2e661af418bbf7074179ea5cfffc0a5c466affected

Linux Linux

Default version status: affected

  • 4.5affected
  • 0 to < 4.5unaffected
  • 5.10.253 to ≤ 5.10.*unaffected
  • 5.15.203 to ≤ 5.15.*unaffected
  • 6.1.167 to ≤ 6.1.*unaffected
  • 6.6.130 to ≤ 6.6.*unaffected
  • 6.12.78 to ≤ 6.12.*unaffected
  • 6.18.19 to ≤ 6.18.*unaffected
  • 6.19.9 to ≤ 6.19.*unaffected
  • 7.0 to ≤ *unaffected

References