GHSA-9Q9R-2G23-7Q72
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33In the Linux kernel, the following vulnerability has been resolved:
sockmap: Fix use-after-free in udp_bpf_recvmsg()
syzbot reported use-after-free of struct sk_msg in sk_msg_recvmsg(). [0]
sk_msg_recvmsg() peeks sk_msg from psock->ingress_msg under a lock, but its processing is lockless.
Thus, sk_msg_recvmsg() must be serialised by callers, otherwise multiple threads could touch the same sk_msg.
For example, TCP uses lock_sock(), and AF_UNIX uses unix_sk(sk)->iolock.
Initially, udp_bpf_recvmsg() had used lock_sock(), but the cited commit removed it.
Let's serialise sk_msg_recvmsg() with lock_sock() in udp_bpf_recvmsg().
Note that holding spin_lock_bh(&sk->sk_receive_queue.lock) is not an option due to copy_page_to_iter() in sk_msg_recvmsg().
[0]: BUG: KASAN: slab-use-after-free in sk_msg_recvmsg+0xb54/0xc30 net/core/skmsg.c:428 Read of size 4 at addr ffff88814cdcf000 by task syz.0.24/6020
CPU: 1 UID: 0 PID: 6020 Comm: syz.0.24 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 sk_msg_recvmsg+0xb54/0xc30 net/core/skmsg.c:428 udp_bpf_recvmsg+0x4bd/0xe00 net/ipv4/udp_bpf.c:84 inet_recvmsg+0x260/0x270 net/ipv4/af_inet.c:891 sock_recvmsg_nosec net/socket.c:1078 [inline] sock_recvmsg+0x1a8/0x270 net/socket.c:1100 _sysrecvmsg+0x1e6/0x4a0 net/socket.c:2812 _sys_recvmsg+0x215/0x590 net/socket.c:2854 do_recvmmsg+0x334/0x800 net/socket.c:2949 __sys_recvmmsg net/socket.c:3023 [inline] __do_sys_recvmmsg net/socket.c:3046 [inline] __se_sys_recvmmsg net/socket.c:3039 [inline] __x64_sys_recvmmsg+0x198/0x250 net/socket.c:3039 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb319f9aeb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb31ad97028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007fb31a216090 RCX: 00007fb319f9aeb9 RDX: 0000000000000001 RSI: 0000200000000400 RDI: 0000000000000004 RBP: 00007fb31a008c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000040000021 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb31a216128 R14: 00007fb31a216090 R15: 00007ffe21dd0a98
Allocated by task 6019: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x3d1/0x6e0 mm/slub.c:5780 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] alloc_sk_msg net/core/skmsg.c:510 [inline] sk_psock_skb_ingress_self+0x60/0x350 net/core/skmsg.c:612 sk_psock_verdict_apply net/core/skmsg.c:1038 [inline] sk_psock_verdict_recv+0x7d9/0x8d0 net/core/skmsg.c:1236 udp_read_skb+0x73e/0x7e0 net/ipv4/udp.c:2045 sk_psock_verdict_data_ready+0x12d/0x550 net/core/skmsg.c:1257 __udp_enqueue_schedule_skb+0xc54/0x10b0 net/ipv4/udp.c:1789 __udp_queue_rcv_skb net/ipv4/udp.c:2346 [inline] udp_queue_rcv_one_skb+0xac5/0x19c0 net/ipv4/udp.c:2475 __udp4_lib_mcast_deliver+0xc06/0xcf0 net/ipv4/udp.c:2585 __udp4_lib_rcv+0x10f6/0x2620 net/ipv4/udp.c:2724 ip_protocol_deliver_rcu+0x282/0x440 net/ipv4/ip_input.c:207 ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 dst_input include/net/dst.h:474 [inline] ip_sublist_rcv_finish+0x221/0x2a0 net/ipv4/ip_input.c:584 ip_list_rcv_finish net/ipv4/ip_inp ---truncated---
{
"affected": [],
"aliases": [
"CVE-2026-74257"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:22:24Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsockmap: Fix use-after-free in udp_bpf_recvmsg()\n\nsyzbot reported use-after-free of struct sk_msg in sk_msg_recvmsg(). [0]\n\nsk_msg_recvmsg() peeks sk_msg from psock-\u003eingress_msg under a lock,\nbut its processing is lockless.\n\nThus, sk_msg_recvmsg() must be serialised by callers, otherwise\nmultiple threads could touch the same sk_msg.\n\nFor example, TCP uses lock_sock(), and AF_UNIX uses unix_sk(sk)-\u003eiolock.\n\nInitially, udp_bpf_recvmsg() had used lock_sock(), but the cited\ncommit removed it.\n\nLet\u0027s serialise sk_msg_recvmsg() with lock_sock() in udp_bpf_recvmsg().\n\nNote that holding spin_lock_bh(\u0026sk-\u003esk_receive_queue.lock) is not\nan option due to copy_page_to_iter() in sk_msg_recvmsg().\n\n[0]:\nBUG: KASAN: slab-use-after-free in sk_msg_recvmsg+0xb54/0xc30 net/core/skmsg.c:428\nRead of size 4 at addr ffff88814cdcf000 by task syz.0.24/6020\n\nCPU: 1 UID: 0 PID: 6020 Comm: syz.0.24 Not tainted syzkaller #0 PREEMPT(full)\nHardware name: Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0xba/0x230 mm/kasan/report.c:482\n kasan_report+0x117/0x150 mm/kasan/report.c:595\n sk_msg_recvmsg+0xb54/0xc30 net/core/skmsg.c:428\n udp_bpf_recvmsg+0x4bd/0xe00 net/ipv4/udp_bpf.c:84\n inet_recvmsg+0x260/0x270 net/ipv4/af_inet.c:891\n sock_recvmsg_nosec net/socket.c:1078 [inline]\n sock_recvmsg+0x1a8/0x270 net/socket.c:1100\n ____sys_recvmsg+0x1e6/0x4a0 net/socket.c:2812\n ___sys_recvmsg+0x215/0x590 net/socket.c:2854\n do_recvmmsg+0x334/0x800 net/socket.c:2949\n __sys_recvmmsg net/socket.c:3023 [inline]\n __do_sys_recvmmsg net/socket.c:3046 [inline]\n __se_sys_recvmmsg net/socket.c:3039 [inline]\n __x64_sys_recvmmsg+0x198/0x250 net/socket.c:3039\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7fb319f9aeb9\nCode: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007fb31ad97028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b\nRAX: ffffffffffffffda RBX: 00007fb31a216090 RCX: 00007fb319f9aeb9\nRDX: 0000000000000001 RSI: 0000200000000400 RDI: 0000000000000004\nRBP: 00007fb31a008c1f R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000040000021 R11: 0000000000000246 R12: 0000000000000000\nR13: 00007fb31a216128 R14: 00007fb31a216090 R15: 00007ffe21dd0a98\n \u003c/TASK\u003e\n\nAllocated by task 6019:\n kasan_save_stack mm/kasan/common.c:57 [inline]\n kasan_save_track+0x3e/0x80 mm/kasan/common.c:78\n poison_kmalloc_redzone mm/kasan/common.c:398 [inline]\n __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415\n kasan_kmalloc include/linux/kasan.h:263 [inline]\n __kmalloc_cache_noprof+0x3d1/0x6e0 mm/slub.c:5780\n kmalloc_noprof include/linux/slab.h:957 [inline]\n kzalloc_noprof include/linux/slab.h:1094 [inline]\n alloc_sk_msg net/core/skmsg.c:510 [inline]\n sk_psock_skb_ingress_self+0x60/0x350 net/core/skmsg.c:612\n sk_psock_verdict_apply net/core/skmsg.c:1038 [inline]\n sk_psock_verdict_recv+0x7d9/0x8d0 net/core/skmsg.c:1236\n udp_read_skb+0x73e/0x7e0 net/ipv4/udp.c:2045\n sk_psock_verdict_data_ready+0x12d/0x550 net/core/skmsg.c:1257\n __udp_enqueue_schedule_skb+0xc54/0x10b0 net/ipv4/udp.c:1789\n __udp_queue_rcv_skb net/ipv4/udp.c:2346 [inline]\n udp_queue_rcv_one_skb+0xac5/0x19c0 net/ipv4/udp.c:2475\n __udp4_lib_mcast_deliver+0xc06/0xcf0 net/ipv4/udp.c:2585\n __udp4_lib_rcv+0x10f6/0x2620 net/ipv4/udp.c:2724\n ip_protocol_deliver_rcu+0x282/0x440 net/ipv4/ip_input.c:207\n ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241\n NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318\n dst_input include/net/dst.h:474 [inline]\n ip_sublist_rcv_finish+0x221/0x2a0 net/ipv4/ip_input.c:584\n ip_list_rcv_finish net/ipv4/ip_inp\n---truncated---",
"id": "GHSA-9q9r-2g23-7q72",
"modified": "2026-08-17T06:33:34Z",
"published": "2026-08-15T06:32:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74257"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/39d44ed6904bfa9a1c6d0538672dd50c7b85520e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/81567d2b3f4dc4fc32f8b61433738bce2cafd4a1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c010995b29c8939c6aa69e3cb26f8dbee163d156"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.