CVE-2026-98401

Что произошло

In the Linux kernel, the following vulnerability has been resolved: net: iptunnel: fix stale transport header during tunnel decapsulation Syzbot reported a crash in qdisc_pkt_len_segs_init() caused by a stale transport_header offset after tunnel decapsulation. BUG: unable to handle page fault for address: ffffed102091a42e Oops: Oops: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 340 Comm: qdisc_uaf_repro Not tainted 7.2.0-rc4-00061-g248951ddc14d #256 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:__asan_load2 qdisc_pkt_len_segs_init (net/core/dev.c:4145) __dev_queue_xmit (net/core/dev.c:4787) br_dev_queue_push_xmit (net/bridge/br_forward.c:53) br_handle_frame_finish (net/bridge/br_input.c:229) br_handle_frame (net/bridge/br_input.c:315) __netif_receive_skb_core.constprop.0 (net/core/dev.c:6099) __netif_receive_skb_list_core (net/core/dev.c:6287) netif_receive_skb_list_internal (net/core/dev.c:6445) napi_complete_done (net/core/dev.c:6813) gro_cell_poll (net/core/gro_cells.c:74) __napi_poll (net/core/dev.c:7735) net_rx_action (net/core/dev.c:7798 net/core/dev.c:7955) handle_softirqs (kernel/softirq.c:622) do_softirq (kernel/softirq.c:523 kernel/softirq.c:510 ) __local_bh_enable_ip (kernel/softirq.c:450) tun_get_user (drivers/net/tun.c:1986 (discriminator 1)) tun_chr_write_iter (drivers/net/tun.c:2032) The issue is completely latent until qdisc read transport header in commit 7fb4c1967011 ("net: pull headers in qdisc_pkt_len_segs_init()"). The crash requires four conditions to line up: 1. The incoming packet is encapsulated and carries GSO metadata. The outer transport header offset is stored in skb->transport_header while the packet is still in the outer tunnel context. 2. The tunnel receiver strips the outer headers. skb->data is advanced to the inner frame, but skb->transport_header is left pointing to the now-removed outer L4 header, so it becomes a negative offset relative to the new data. 3. The inner frame is not delivered to the local IP stack. Instead, it is forwarded at L2 by a bridge or HSR, so ip_rcv_core() never runs and the transport header is not reset to the inner L4 offset. 4. The forwarding path calls __dev_queue_xmit(), which enters qdisc_pkt_len_segs_init(). That function computes the GSO header length from skb_transport_offset(skb). Because the offset is negative, the unsigned cast overflows and pskb_may_pull(skb, hdr_len + sizeof(struct tcphdr)) reads past the end of the skb, triggering a KASAN fault or page fault. The issue specifically requires GSO packets (shinfo->gso_size != 0), which are processed/aggregated through gro_cells. Fix this by clearing transport_header to the ~0U sentinel in gro_cell for all tunnnel driver. GTP does not support GRO/GSO, drop the evil GSO packets in GTP directly.

Что делать

dpkg-query -W -f='${Package}	${Version}\n'

rpm -qa --qf '%{NAME}\t%{VERSION}-%{RELEASE}\n'

Get-HotFix | Select-Object HotFixID, InstalledOn

Продукты и затронутые версии

{
  "status": "affected",
  "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
  "lessThan": "8c3d4dfcecf7670c1d752f1ae74b21b2af5feac1",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
  "lessThan": "e4a5b01e59f7102169762b8f566c8e052d05c0ff",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
  "lessThan": "3340b8565b85631cfeb0df049e8b46e3ef8bd7bd",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
  "lessThan": "28a57fb2c5df4deb42a06e52fd36c14b37aa0034",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "2.6.12"
}

{
  "status": "unaffected",
  "version": "0",
  "lessThan": "2.6.12",
  "versionType": "semver"
}

{
  "status": "unaffected",
  "version": "6.12.111",
  "versionType": "semver",
  "lessThanOrEqual": "6.12.*"
}

{
  "status": "unaffected",
  "version": "6.18.53",
  "versionType": "semver",
  "lessThanOrEqual": "6.18.*"
}

{
  "status": "unaffected",
  "version": "7.2.7",
  "versionType": "semver",
  "lessThanOrEqual": "7.2.*"
}

{
  "status": "unaffected",
  "version": "7.3",
  "versionType": "original_commit_for_fix",
  "lessThanOrEqual": "*"
}

CVSS: оценки и векторы

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Источники и ссылки

{
  "cwes": [],
  "epss": {
    "source": "epss",
    "received_at": "2026-11-03T21:16:05.845896+00:00"
  },
  "title": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.411851+00:00"
  },
  "scores": [
    "cve"
  ],
  "status": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.411851+00:00"
  },
  "affected": [
    "cve"
  ],
  "published": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.411851+00:00"
  },
  "solutions": [],
  "percentile": {
    "source": "epss",
    "received_at": "2026-11-03T21:16:05.845896+00:00"
  },
  "references": [
    "cve"
  ],
  "description": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.411851+00:00"
  },
  "workarounds": [],
  "configurations": []
}

Хронология записи

1. Данные обновлены04.11.2026, 00:16
2. Данные обновлены03.11.2026, 00:15
3. Данные обновлены02.11.2026, 00:13
4. Данные обновлены31.10.2026, 12:00
5. Данные обновлены29.10.2026, 12:47
6. Опубликована28.10.2026, 23:13

Личная заметка и статус

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