CVE-2026-98022

Что произошло

In the Linux kernel, the following vulnerability has been resolved: net: cap tx_queue_len at S16_MAX to prevent oversized ring allocations Several subsystems allocate ring buffers sized by dev->tx_queue_len with no upper bound. An unprivileged user (via unshare -Urn) can set a huge tx_queue_len and exhaust global memory with ring allocations: - pfifo_fast: pfifo_fast_init() and pfifo_fast_change_tx_queue_len() allocate 3 skb_array rings of tx_queue_len entries each. - tun: tun_queue_resize() and the queue-attach path resize ptr_rings to tx_queue_len on the NETDEV_CHANGE_TX_QUEUE_LEN notifier. - tap (macvtap/ipvtap): tap_queue_resize() and tap_init() resize/init ptr_rings to tx_queue_len on the same notifier. netif_change_tx_queue_len() is the single entry point for IFLA_TXQLEN, sysfs, and the SIOCSIFTXQLEN ioctl. Cap new_len at S16_MAX (32767) there so the oversized value is rejected at set time. This takes effect whether the device is up or down, before dev->tx_queue_len is written, before any notifier fires, and before any ring is allocated. The "> S16_MAX" check also subsumes the previous unsigned-long truncation test, and a negative ifr_qlen from the ioctl lands far above the cap after conversion, so both old failure modes are covered by the one comparison. tx_queue_len is ambigious: both a per-ring sizing multiplier and a default queue-length/limit knob for consumers that allocate nothing at set time (pfifo/bfifo/gred/plug/sfb limits, htb direct_qlen, qfq max_classes, teql). 32767 is chosen as the largest value NLA_POLICY_FULL_RANGE can express for the u32 IFLA_TXQLEN policy in patch 2/3 while staying a legitimate queue length on high-BDP paths; the ring-memory trade-off of a shared knob is disclosed below. Conditions to recreate the bug: - CONFIG_NET_SCHED=y, CONFIG_VETH=y, CONFIG_USER_NS=y, CONFIG_NET_NS=y. - Unprivileged user in a fresh user+net namespace (unshare -Urn). - pfifo_fast: create veth pairs, set tx_queue_len to 500000, attach mq+pfifo_fast. ~28 iterations OOMs a 2GB guest. - tun: create 50 tun devices with IFF_MULTI_QUEUE, set tx_queue_len to 500000, open 8 queues each. ~1.6GB of ptr_ring allocations OOMs a 512MB guest. - tap: same as tun with IFF_TAP. ~960MB OOMs a 512MB guest. - On the fixed kernel the oversized tx_queue_len is rejected with -ERANGE at set time (all four paths: RTM_SETLINK, RTM_NEWLINK create, sysfs, ioctl - the latter two via this check, the former two via this check and the 2/3 parse policy respectively).

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": "6a643ddb5624be7e0694d49f5765a8d41c1ab6d0",
  "lessThan": "24d02c909a1725ab9eceb92db7d02e4e841f17ca",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "6a643ddb5624be7e0694d49f5765a8d41c1ab6d0",
  "lessThan": "5e5591a0f33f7c11bf1d338dbb6c5072575de64c",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "6a643ddb5624be7e0694d49f5765a8d41c1ab6d0",
  "lessThan": "c8d4060610c69645733c92d94fceb4b93808ac4d",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "6a643ddb5624be7e0694d49f5765a8d41c1ab6d0",
  "lessThan": "c2362c500931e5bd1826bce34e9ce28af80e7541",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "6a643ddb5624be7e0694d49f5765a8d41c1ab6d0",
  "lessThan": "81c0e02076989743a603806a5a4f44d2c40dc01f",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "6a643ddb5624be7e0694d49f5765a8d41c1ab6d0",
  "lessThan": "081340cf70a789b94b4174af54a63ffd49677a4e",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "6a643ddb5624be7e0694d49f5765a8d41c1ab6d0",
  "lessThan": "a03b927bae4af5c23fd5315a237855c17cc8f422",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "6a643ddb5624be7e0694d49f5765a8d41c1ab6d0",
  "lessThan": "66ab4c59b74db7ab53a1c9083feaaede393a96a0",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "4.16"
}

{
  "status": "unaffected",
  "version": "0",
  "lessThan": "4.16",
  "versionType": "semver"
}

{
  "status": "unaffected",
  "version": "5.10.271",
  "versionType": "semver",
  "lessThanOrEqual": "5.10.*"
}

{
  "status": "unaffected",
  "version": "5.15.222",
  "versionType": "semver",
  "lessThanOrEqual": "5.15.*"
}

{
  "status": "unaffected",
  "version": "6.1.189",
  "versionType": "semver",
  "lessThanOrEqual": "6.1.*"
}

{
  "status": "unaffected",
  "version": "6.6.158",
  "versionType": "semver",
  "lessThanOrEqual": "6.6.*"
}

{
  "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

Оценка CVSS отсутствует.

Источники и ссылки

{
  "cwes": [],
  "epss": {
    "source": "epss",
    "received_at": "2026-11-02T21:15:43.965766+00:00"
  },
  "title": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.294858+00:00"
  },
  "scores": [],
  "status": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.294858+00:00"
  },
  "affected": [
    "cve"
  ],
  "published": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.294858+00:00"
  },
  "solutions": [],
  "percentile": {
    "source": "epss",
    "received_at": "2026-11-02T21:15:43.965766+00:00"
  },
  "references": [
    "cve"
  ],
  "description": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.294858+00:00"
  },
  "workarounds": [],
  "configurations": []
}

Хронология записи

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

Личная заметка и статус

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