{"id":"CVE-2023-53500","summary":"xfrm: fix slab-use-after-free in decode_session6","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: fix slab-use-after-free in decode_session6\n\nWhen the xfrm device is set to the qdisc of the sfb type, the cb field\nof the sent skb may be modified during enqueuing. Then,\nslab-use-after-free may occur when the xfrm device sends IPv6 packets.\n\nThe stack information is as follows:\nBUG: KASAN: slab-use-after-free in decode_session6+0x103f/0x1890\nRead of size 1 at addr ffff8881111458ef by task swapper/3/0\nCPU: 3 PID: 0 Comm: swapper/3 Not tainted 6.4.0-next-20230707 #409\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014\nCall Trace:\n\u003cIRQ\u003e\ndump_stack_lvl+0xd9/0x150\nprint_address_description.constprop.0+0x2c/0x3c0\nkasan_report+0x11d/0x130\ndecode_session6+0x103f/0x1890\n__xfrm_decode_session+0x54/0xb0\nxfrmi_xmit+0x173/0x1ca0\ndev_hard_start_xmit+0x187/0x700\nsch_direct_xmit+0x1a3/0xc30\n__qdisc_run+0x510/0x17a0\n__dev_queue_xmit+0x2215/0x3b10\nneigh_connected_output+0x3c2/0x550\nip6_finish_output2+0x55a/0x1550\nip6_finish_output+0x6b9/0x1270\nip6_output+0x1f1/0x540\nndisc_send_skb+0xa63/0x1890\nndisc_send_rs+0x132/0x6f0\naddrconf_rs_timer+0x3f1/0x870\ncall_timer_fn+0x1a0/0x580\nexpire_timers+0x29b/0x4b0\nrun_timer_softirq+0x326/0x910\n__do_softirq+0x1d4/0x905\nirq_exit_rcu+0xb7/0x120\nsysvec_apic_timer_interrupt+0x97/0xc0\n\u003c/IRQ\u003e\n\u003cTASK\u003e\nasm_sysvec_apic_timer_interrupt+0x1a/0x20\nRIP: 0010:intel_idle_hlt+0x23/0x30\nCode: 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 \u003cfa\u003e 44 89 e0 41 5c c3 66 0f 1f 44 00 00 f3 0f 1e fa 41 54 41 89 d4\nRSP: 0018:ffffc90000197d78 EFLAGS: 00000246\nRAX: 00000000000a83c3 RBX: ffffe8ffffd09c50 RCX: ffffffff8a22d8e5\nRDX: 0000000000000001 RSI: ffffffff8d3f8080 RDI: ffffe8ffffd09c50\nRBP: ffffffff8d3f8080 R08: 0000000000000001 R09: ffffed1026ba6d9d\nR10: ffff888135d36ceb R11: 0000000000000001 R12: 0000000000000001\nR13: ffffffff8d3f8100 R14: 0000000000000001 R15: 0000000000000000\ncpuidle_enter_state+0xd3/0x6f0\ncpuidle_enter+0x4e/0xa0\ndo_idle+0x2fe/0x3c0\ncpu_startup_entry+0x18/0x20\nstart_secondary+0x200/0x290\nsecondary_startup_64_no_verify+0x167/0x16b\n\u003c/TASK\u003e\nAllocated by task 939:\nkasan_save_stack+0x22/0x40\nkasan_set_track+0x25/0x30\n__kasan_slab_alloc+0x7f/0x90\nkmem_cache_alloc_node+0x1cd/0x410\nkmalloc_reserve+0x165/0x270\n__alloc_skb+0x129/0x330\ninet6_ifa_notify+0x118/0x230\n__ipv6_ifa_notify+0x177/0xbe0\naddrconf_dad_completed+0x133/0xe00\naddrconf_dad_work+0x764/0x1390\nprocess_one_work+0xa32/0x16f0\nworker_thread+0x67d/0x10c0\nkthread+0x344/0x440\nret_from_fork+0x1f/0x30\nThe buggy address belongs to the object at ffff888111145800\nwhich belongs to the cache skbuff_small_head of size 640\nThe buggy address is located 239 bytes inside of\nfreed 640-byte region [ffff888111145800, ffff888111145a80)\n\nAs commit f855691975bb (\"xfrm6: Fix the nexthdr offset in\n_decode_session6.\") showed, xfrm_decode_session was originally intended\nonly for the receive path. IP6CB(skb)-\u003enhoff is not set during\ntransmission. Therefore, set the cb field in the skb to 0 before\nsending packets.","modified":"2026-05-18T05:55:33.723366717Z","published":"2025-10-01T11:45:51.182Z","related":["SUSE-SU-2025:03600-1","SUSE-SU-2025:03634-1","SUSE-SU-2025:20851-1","SUSE-SU-2025:20861-1","SUSE-SU-2025:20870-1","SUSE-SU-2025:20898-1","SUSE-SU-2025:3751-1","SUSE-SU-2025:4057-1","SUSE-SU-2025:4111-1","SUSE-SU-2025:4132-1","SUSE-SU-2025:4135-1","SUSE-SU-2025:4139-1","SUSE-SU-2025:4141-1","SUSE-SU-2025:4149-1","SUSE-SU-2025:4188-1","SUSE-SU-2025:4320-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53500.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0d27567fde5be5f0edc2db5c110142b7915b8fa8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/44b3d40967009304617a7a6486490c1d6c12f899"},{"type":"WEB","url":"https://git.kernel.org/stable/c/53223f2ed1ef5c90dad814daaaefea4e68a933c8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/86f15300a22656db3fa8c8967defbcd24fac4d37"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bafa236380816b41b2c4c6970d9067fefa4a6c9e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/da4cbaa75ed088b6d70db77b9103a27e2359e243"},{"type":"WEB","url":"https://git.kernel.org/stable/c/db0e50741f0387f388e9ec824ea7ae8456554d5b"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53500.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-53500"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f855691975bb06373a98711e4cfe2c224244b536"},{"fixed":"da4cbaa75ed088b6d70db77b9103a27e2359e243"},{"fixed":"db0e50741f0387f388e9ec824ea7ae8456554d5b"},{"fixed":"bafa236380816b41b2c4c6970d9067fefa4a6c9e"},{"fixed":"44b3d40967009304617a7a6486490c1d6c12f899"},{"fixed":"0d27567fde5be5f0edc2db5c110142b7915b8fa8"},{"fixed":"86f15300a22656db3fa8c8967defbcd24fac4d37"},{"fixed":"53223f2ed1ef5c90dad814daaaefea4e68a933c8"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2023-53500.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.19.0"},{"fixed":"4.19.293"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.20.0"},{"fixed":"5.4.255"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.192"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.128"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.47"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.4.12"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2023-53500.json"}}],"schema_version":"1.7.5"}