CVE-2026-98393

Что произошло

In the Linux kernel, the following vulnerability has been resolved: net: ipv4: Fix UDP length overflow with PMTU discover and big MTU This commit bounds cork->base.fragsize to IP_MAX_MTU to avoid a possible overflow of UDP length that triggers a WARN in udp_set_len_short when setsockopt IP_MTU_DISCOVER is set to IP_PMTUDISC_PROBE, and a large packet is sent over a netdev with an unusually large MTU. Steps to reproduce: 1. Set device MTU bigger than IP_MAX_MTU + 20. cork->base.fragsize will be set to that MTU in ip_setup_cork. 2. Set IP_MTU_DISCOVER to IP_PMTUDISC_PROBE. It lets maxnonfragsize be set to device MTU (cork->fragsize) in __ip_append_data, rather than to IP_MAX_MTU. 3. Send 65528 bytes of payload (+8 bytes of UDP header, +20 bytes of IPv4 header). Device MTU allows it (it's only one byte bigger than IP_MAX_MTU + IPv4 header, and the device MTU is bigger than that). 4. The UDP length in the built packet is 65536, which overflows the 16-bit length field and triggers the WARN in udp_set_len_short. Note: IP_PMTUDISC_DO with IPv4 is safe, because ip_dst_mtu_maybe_forward always clamps at IP_MAX_MTU, unlike ip6_dst_mtu_maybe_forward. The Fixes tag points at the first commit where I could reproduce the overflow with IPv4 and IP_PMTUDISC_PROBE.

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": "daba287b299ec7a2c61ae3a714920e90e8396ad5",
  "lessThan": "83fedc4741210f75be8ca5b487985a242bf6f18d",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "daba287b299ec7a2c61ae3a714920e90e8396ad5",
  "lessThan": "81f540827d243b8dad76c1f44e70ea31719f393c",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "daba287b299ec7a2c61ae3a714920e90e8396ad5",
  "lessThan": "b83641e0ab8b20eefcc4cdc5a059f897375291a2",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "3.13"
}

{
  "status": "unaffected",
  "version": "0",
  "lessThan": "3.13",
  "versionType": "semver"
}

{
  "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": "2026-11-02T21:15:46.207831+00:00"
  },
  "title": {
    "source": "cve",
    "received_at": "2026-10-28T20:17:16.414792+00:00"
  },
  "scores": [],
  "status": {
    "source": "cve",
    "received_at": "2026-10-28T20:17:16.414792+00:00"
  },
  "affected": [
    "cve"
  ],
  "published": {
    "source": "cve",
    "received_at": "2026-10-28T20:17:16.414792+00:00"
  },
  "solutions": [],
  "percentile": {
    "source": "epss",
    "received_at": "2026-11-02T21:15:46.207831+00:00"
  },
  "references": [
    "cve"
  ],
  "description": {
    "source": "cve",
    "received_at": "2026-10-28T20:17:16.414792+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, 23:17

Личная заметка и статус

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