In the Linux kernel, the following vulnerability has been resolved:
xfrm: fix slab-use-after-free in decode_session6
When the xfrm device is set to the qdisc of the sfb type, the cb field of the sent skb may be modified during enqueuing. Then, slab-use-after-free may occur when the xfrm device sends IPv6 packets.
The stack information is as follows: BUG: KASAN: slab-use-after-free in decode_session6+0x103f/0x1890 Read of size 1 at addr ffff8881111458ef by task swapper/3/0 CPU: 3 PID: 0 Comm: swapper/3 Not tainted 6.4.0-next-20230707 #409 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 Call Trace: <IRQ> dump_stack_lvl+0xd9/0x150 print_address_description.constprop.0+0x2c/0x3c0 kasan_report+0x11d/0x130 decode_session6+0x103f/0x1890 __xfrm_decode_session+0x54/0xb0 xfrmi_xmit+0x173/0x1ca0 dev_hard_start_xmit+0x187/0x700 sch_direct_xmit+0x1a3/0xc30 __qdisc_run+0x510/0x17a0 __dev_queue_xmit+0x2215/0x3b10 neigh_connected_output+0x3c2/0x550 ip6_finish_output2+0x55a/0x1550 ip6_finish_output+0x6b9/0x1270 ip6_output+0x1f1/0x540 ndisc_send_skb+0xa63/0x1890 ndisc_send_rs+0x132/0x6f0 addrconf_rs_timer+0x3f1/0x870 call_timer_fn+0x1a0/0x580 expire_timers+0x29b/0x4b0 run_timer_softirq+0x326/0x910 __do_softirq+0x1d4/0x905 irq_exit_rcu+0xb7/0x120 sysvec_apic_timer_interrupt+0x97/0xc0 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x1a/0x20 RIP: 0010:intel_idle_hlt+0x23/0x30 Code: 1f 84 00 00 00 00 00 f3 0f 1e fa 41 54 41 89 d4 0f 1f 44 00 00 66 90 0f 1f 44 00 00 0f 00 2d c4 9f ab 00 0f 1f 44 00 00 fb f4 <fa> 44 89 e0 41 5c c3 66 0f 1f 44 00 00 f3 0f 1e fa 41 54 41 89 d4 RSP: 0018:ffffc90000197d78 EFLAGS: 00000246 RAX: 00000000000a83c3 RBX: ffffe8ffffd09c50 RCX: ffffffff8a22d8e5 RDX: 0000000000000001 RSI: ffffffff8d3f8080 RDI: ffffe8ffffd09c50 RBP: ffffffff8d3f8080 R08: 0000000000000001 R09: ffffed1026ba6d9d R10: ffff888135d36ceb R11: 0000000000000001 R12: 0000000000000001 R13: ffffffff8d3f8100 R14: 0000000000000001 R15: 0000000000000000 cpuidle_enter_state+0xd3/0x6f0 cpuidle_enter+0x4e/0xa0 do_idle+0x2fe/0x3c0 cpu_startup_entry+0x18/0x20 start_secondary+0x200/0x290 secondary_startup_64_no_verify+0x167/0x16b </TASK> Allocated by task 939: kasan_save_stack+0x22/0x40 kasan_set_track+0x25/0x30 __kasan_slab_alloc+0x7f/0x90 kmem_cache_alloc_node+0x1cd/0x410 kmalloc_reserve+0x165/0x270 __alloc_skb+0x129/0x330 inet6_ifa_notify+0x118/0x230 __ipv6_ifa_notify+0x177/0xbe0 addrconf_dad_completed+0x133/0xe00 addrconf_dad_work+0x764/0x1390 process_one_work+0xa32/0x16f0 worker_thread+0x67d/0x10c0 kthread+0x344/0x440 ret_from_fork+0x1f/0x30 The buggy address belongs to the object at ffff888111145800 which belongs to the cache skbuff_small_head of size 640 The buggy address is located 239 bytes inside of freed 640-byte region [ffff888111145800, ffff888111145a80)
As commit f855691975bb ("xfrm6: Fix the nexthdr offset in _decode_session6.") showed, xfrm_decode_session was originally intended only for the receive path. IP6CB(skb)->nhoff is not set during transmission. Therefore, set the cb field in the skb to 0 before sending packets.
CVSS Details
- CVSS 3.1 Base Score: 7.3
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade kernel-livepatch-5.10.192-182.736Upgrade bpftoolUpgrade python-perfUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-livepatch-5.15.128-80.144Upgrade kernel-tools-debuginfoUpgrade kernel-develUpgrade bpftool-debuginfoUpgrade kernel-debuginfoUpgrade perf-debuginfoUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-toolsUpgrade kernel-headersUpgrade kernel-tools-develUpgrade kernelUpgrade perfUpgrade python-perf-debuginfo | May 20, 2026 | May 20, 2026 |
| Amazon_linux_2023 | — | Upgrade kernel-debuginfo-common-aarch64Upgrade kernel-debuginfoUpgrade kernel-tools-develUpgrade kernel-libbpf-develUpgrade kernel-libbpfUpgrade bpftoolUpgrade kernel-livepatch-6.1.49-69.116Upgrade python3-perf-debuginfoUpgrade python3-perfUpgrade kernel-tools-debuginfoUpgrade kernelUpgrade kernel-develUpgrade perfUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-libbpf-staticUpgrade perf-debuginfoUpgrade kernel-headersUpgrade bpftool-debuginfoUpgrade kernel-tools | Oct 16, 2025 | Oct 1, 2025 |
| Debian | — | Upgrade linux | Oct 3, 2025 | Oct 3, 2025 |
| Huawei Euleros 2_0_sp10 | — | Upgrade kernel-abi-stablelistsUpgrade kernel-tools-libsUpgrade kernel-toolsUpgrade kernelUpgrade python3-perf | Jan 15, 2026 | Jan 13, 2026 |
| Huawei Euleros 2_0_sp13 | — | Upgrade python3-perfUpgrade kernel-abi-stablelistsUpgrade kernel-toolsUpgrade kernelUpgrade bpftoolUpgrade kernel-tools-libs | Feb 3, 2026 | Jan 30, 2026 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Oct 1, 2025 |
| Ubuntu | — | Upgrade linux-gcp-5.4Upgrade linux-ibm-5.15Upgrade linux-nvidiaUpgrade linux-azure-fipsUpgrade linux-aws-fipsUpgrade linux-intel-iotgUpgrade linux-intel-iot-realtimeUpgrade linux-azure-5.4Upgrade linux-lowlatencyUpgrade linux-oracle-5.15Upgrade linux-hwe-5.15Upgrade linux-gkeopUpgrade linux-gcp-5.15Upgrade linux-nvidia-tegra-igxUpgrade linux-gkeUpgrade linux-gcpUpgrade linux-riscv-5.15Upgrade linux-ibmUpgrade linux-hwe-5.4Upgrade linux-gcp-fipsUpgrade linux-realtimeUpgrade linux-intel-iotg-5.15Upgrade linux-raspiUpgrade linux-kvmUpgrade linux-aws-5.4Upgrade linux-azure-5.15Upgrade linux-fipsUpgrade linux-xilinx-zynqmpUpgrade linux-oracleUpgrade linux-azureUpgrade linux-raspi-5.4Upgrade linux-awsUpgrade linux-lowlatency-hwe-5.15Upgrade linux-ibm-5.4Upgrade linux-aws-5.15Upgrade linux-nvidia-tegra-5.15Upgrade linux-oracle-5.4Upgrade linux-iotUpgrade linux-nvidia-tegraUpgrade linux-bluefieldUpgrade linux | Oct 10, 2025 | Oct 1, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Oct 15, 2025 | Oct 1, 2025 |
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