ghsa-mrx6-v6w2-5q3x
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
net: drop UFO packets in udp_rcv_segment()
When sending a packet with virtio_net_hdr to tun device, if the gso_type in virtio_net_hdr is SKB_GSO_UDP and the gso_size is less than udphdr size, below crash may happen.
------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:4572! Oops: invalid opcode: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 62 Comm: mytest Not tainted 6.16.0-rc7 #203 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:skb_pull_rcsum+0x8e/0xa0 Code: 00 00 5b c3 cc cc cc cc 8b 93 88 00 00 00 f7 da e8 37 44 38 00 f7 d8 89 83 88 00 00 00 48 8b 83 c8 00 00 00 5b c3 cc cc cc cc <0f> 0b 0f 0b 66 66 2e 0f 1f 84 00 000 RSP: 0018:ffffc900001fba38 EFLAGS: 00000297 RAX: 0000000000000004 RBX: ffff8880040c1000 RCX: ffffc900001fb948 RDX: ffff888003e6d700 RSI: 0000000000000008 RDI: ffff88800411a062 RBP: ffff8880040c1000 R08: 0000000000000000 R09: 0000000000000001 R10: ffff888003606c00 R11: 0000000000000001 R12: 0000000000000000 R13: ffff888004060900 R14: ffff888004050000 R15: ffff888004060900 FS: 000000002406d3c0(0000) GS:ffff888084a19000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000040 CR3: 0000000004007000 CR4: 00000000000006f0 Call Trace: udp_queue_rcv_one_skb+0x176/0x4b0 net/ipv4/udp.c:2445 udp_queue_rcv_skb+0x155/0x1f0 net/ipv4/udp.c:2475 udp_unicast_rcv_skb+0x71/0x90 net/ipv4/udp.c:2626 __udp4_lib_rcv+0x433/0xb00 net/ipv4/udp.c:2690 ip_protocol_deliver_rcu+0xa6/0x160 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x72/0x90 net/ipv4/ip_input.c:233 ip_sublist_rcv_finish+0x5f/0x70 net/ipv4/ip_input.c:579 ip_sublist_rcv+0x122/0x1b0 net/ipv4/ip_input.c:636 ip_list_rcv+0xf7/0x130 net/ipv4/ip_input.c:670 __netif_receive_skb_list_core+0x21d/0x240 net/core/dev.c:6067 netif_receive_skb_list_internal+0x186/0x2b0 net/core/dev.c:6210 napi_complete_done+0x78/0x180 net/core/dev.c:6580 tun_get_user+0xa63/0x1120 drivers/net/tun.c:1909 tun_chr_write_iter+0x65/0xb0 drivers/net/tun.c:1984 vfs_write+0x300/0x420 fs/read_write.c:593 ksys_write+0x60/0xd0 fs/read_write.c:686 do_syscall_64+0x50/0x1c0 arch/x86/entry/syscall_64.c:63
To trigger gso segment in udp_queue_rcv_skb(), we should also set option UDP_ENCAP_ESPINUDP to enable udp_sk(sk)->encap_rcv. When the encap_rcv hook return 1 in udp_queue_rcv_one_skb(), udp_csum_pull_header() will try to pull udphdr, but the skb size has been segmented to gso size, which leads to this crash.
Previous commit cf329aa42b66 ("udp: cope with UDP GRO packet misdirection") introduces segmentation in UDP receive path only for GRO, which was never intended to be used for UFO, so drop UFO packets in udp_rcv_segment().
{
"affected": [],
"aliases": [
"CVE-2025-38622"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-08-22T16:15:35Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: drop UFO packets in udp_rcv_segment()\n\nWhen sending a packet with virtio_net_hdr to tun device, if the gso_type\nin virtio_net_hdr is SKB_GSO_UDP and the gso_size is less than udphdr\nsize, below crash may happen.\n\n ------------[ cut here ]------------\n kernel BUG at net/core/skbuff.c:4572!\n Oops: invalid opcode: 0000 [#1] SMP NOPTI\n CPU: 0 UID: 0 PID: 62 Comm: mytest Not tainted 6.16.0-rc7 #203 PREEMPT(voluntary)\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014\n RIP: 0010:skb_pull_rcsum+0x8e/0xa0\n Code: 00 00 5b c3 cc cc cc cc 8b 93 88 00 00 00 f7 da e8 37 44 38 00 f7 d8 89 83 88 00 00 00 48 8b 83 c8 00 00 00 5b c3 cc cc cc cc \u003c0f\u003e 0b 0f 0b 66 66 2e 0f 1f 84 00 000\n RSP: 0018:ffffc900001fba38 EFLAGS: 00000297\n RAX: 0000000000000004 RBX: ffff8880040c1000 RCX: ffffc900001fb948\n RDX: ffff888003e6d700 RSI: 0000000000000008 RDI: ffff88800411a062\n RBP: ffff8880040c1000 R08: 0000000000000000 R09: 0000000000000001\n R10: ffff888003606c00 R11: 0000000000000001 R12: 0000000000000000\n R13: ffff888004060900 R14: ffff888004050000 R15: ffff888004060900\n FS: 000000002406d3c0(0000) GS:ffff888084a19000(0000) knlGS:0000000000000000\n CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 0000000020000040 CR3: 0000000004007000 CR4: 00000000000006f0\n Call Trace:\n \u003cTASK\u003e\n udp_queue_rcv_one_skb+0x176/0x4b0 net/ipv4/udp.c:2445\n udp_queue_rcv_skb+0x155/0x1f0 net/ipv4/udp.c:2475\n udp_unicast_rcv_skb+0x71/0x90 net/ipv4/udp.c:2626\n __udp4_lib_rcv+0x433/0xb00 net/ipv4/udp.c:2690\n ip_protocol_deliver_rcu+0xa6/0x160 net/ipv4/ip_input.c:205\n ip_local_deliver_finish+0x72/0x90 net/ipv4/ip_input.c:233\n ip_sublist_rcv_finish+0x5f/0x70 net/ipv4/ip_input.c:579\n ip_sublist_rcv+0x122/0x1b0 net/ipv4/ip_input.c:636\n ip_list_rcv+0xf7/0x130 net/ipv4/ip_input.c:670\n __netif_receive_skb_list_core+0x21d/0x240 net/core/dev.c:6067\n netif_receive_skb_list_internal+0x186/0x2b0 net/core/dev.c:6210\n napi_complete_done+0x78/0x180 net/core/dev.c:6580\n tun_get_user+0xa63/0x1120 drivers/net/tun.c:1909\n tun_chr_write_iter+0x65/0xb0 drivers/net/tun.c:1984\n vfs_write+0x300/0x420 fs/read_write.c:593\n ksys_write+0x60/0xd0 fs/read_write.c:686\n do_syscall_64+0x50/0x1c0 arch/x86/entry/syscall_64.c:63\n \u003c/TASK\u003e\n\nTo trigger gso segment in udp_queue_rcv_skb(), we should also set option\nUDP_ENCAP_ESPINUDP to enable udp_sk(sk)-\u003eencap_rcv. When the encap_rcv\nhook return 1 in udp_queue_rcv_one_skb(), udp_csum_pull_header() will try\nto pull udphdr, but the skb size has been segmented to gso size, which\nleads to this crash.\n\nPrevious commit cf329aa42b66 (\"udp: cope with UDP GRO packet misdirection\")\nintroduces segmentation in UDP receive path only for GRO, which was never\nintended to be used for UFO, so drop UFO packets in udp_rcv_segment().",
"id": "GHSA-mrx6-v6w2-5q3x",
"modified": "2025-08-28T15:30:39Z",
"published": "2025-08-22T18:31:21Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38622"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0c639c6479ec4480372901a5fc566f7588cf5522"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0d45954034f8edd6d4052e0190d3d6335c37e4de"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4c1022220b1b6fea802175e80444923a3bbf93a5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/72f97d3cb791e26492236b2be7fd70d2c6222555"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/791f32c5eab33ca3a153f8f6f763aa0df1ddc320"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c0ec2e47f1e92d69b42b17a4a1e543256778393e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d46e51f1c78b9ab9323610feb14238d06d46d519"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/df6ad849d59256dcc0e2234844ef9f0daf885f5c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fc45b3f9599b657d4a64bcf423d2a977b3e13a49"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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