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CVE PROGRAM SOURCE RECORD7.5 High

CVE-2026-89561

ipv6: rpl: fix NULL dereference of idev in ipv6_rpl_srh_rcv()

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: rpl: fix NULL dereference of idev in ipv6_rpl_srh_rcv() ipv6_rpl_srh_rcv() dereferences idev from __in6_dev_get() without a NULL check when reading idev->cnf.rpl_seg_enabled. When the device's MTU drops below IPV6_MIN_MTU, addrconf_ifdown() clears dev->ip6_ptr through RCU_INIT_POINTER(). A packet that passed the idev check in ip6_rcv_core() can then reach ipv6_rpl_srh_rcv() with dev->ip6_ptr already NULL. Reproduced by flooding the receiving interface with ping6 traffic while flapping its MTU between 1500 and 1200: BUG: KASAN: null-ptr-deref in ipv6_rpl_srh_rcv+0xb3/0x1070 Read of size 4 at addr 00000000000006b4 by task ping6/394 CPU: 2 UID: 0 PID: 394 Comm: ping6 Not tainted 7.2.0-rc7-micro-vm-dev-00095-g24ef02f934ee #240 PREEMPT(full) Call Trace: <IRQ> kasan_report+0xc6/0x100 ipv6_rpl_srh_rcv+0xb3/0x1070 ip6_protocol_deliver_rcu+0x759/0x9a0 ip6_input_finish+0xa8/0x1b0 ip6_input+0xe1/0x490 ipv6_rcv+0x33d/0x460 __netif_receive_skb_one_core+0xd6/0x130 process_backlog+0x2cc/0xa00 __napi_poll.constprop.0+0x56/0x270 net_rx_action+0x327/0x730 handle_softirqs+0x11e/0x630 do_softirq+0xb3/0xf0 </IRQ> Both ipv6_rpl_srh_rcv() and ipv6_srh_rcv() are called only from ipv6_rthdr_rcv(), which already has an idev lookup. Fix the NULL dereference on the RPL path by checking idev in ipv6_rthdr_rcv(), before it calls either function. The callees take idev as an argument and no longer call __in6_dev_get(), so the packet is now dropped in one place, with SKB_DROP_REASON_IPV6DISABLED on both paths.

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

  • 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3 to < f5e89dfc0a815c6ed12791d8deb3b6f39dd0621eaffected
  • 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3 to < 62b63a505c10e8db76017ef73c0b243e0dc5d288affected
  • 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3 to < e7123e10c86eb88eaa90537dd1f232706de2d308affected
  • 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3 to < 63f50e9f90d0287ad66a0955ebfc2d3a9c044a1caffected
  • 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3 to < eab3a917cdcb182542a3aac6a0d2d30659ca9821affected
  • 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3 to < f826df95332c07380206dbd54178b6eefb311abaaffected

Linux Linux

Default version status: affected

  • 5.7affected
  • 0 to < 5.7unaffected
  • 6.1.191 to ≤ 6.1.*unaffected
  • 6.6.160 to ≤ 6.6.*unaffected
  • 6.12.111 to ≤ 6.12.*unaffected
  • 6.18.50 to ≤ 6.18.*unaffected
  • 7.2.4 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References