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net: reject oversized tx_queue_len at netlink parse time

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net: reject oversized tx_queue_len at netlink parse time rtnl_create_link() assigns IFLA_TXQLEN directly to dev->tx_queue_len without going through netif_change_tx_queue_len(), so a device created with "ip link add ... txqueuelen 500000" bypasses the S16_MAX cap and still triggers the oversized ring allocations in pfifo_fast, tun and tap. The veth peer nest (rtnl_nla_parse_ifinfomsg()) and the RTM_NEWLINK-on-existing-device path reach the same sinks. Enforce the cap in ifla_policy instead: IFLA_TXQLEN becomes NLA_POLICY_FULL_RANGE(NLA_U32, &txqlen_range) with txqlen_range = { .min = 0, .max = S16_MAX }. All netlink consumers parse against this policy - rtnl_setlink(), rtnl_newlink() (create and change), and the veth peer nest - so every netlink path is capped at parse time and rejects the attribute with -ERANGE plus a proper "integer out of range" extack message before any device state is modified (the RTM_SETLINK half-application wart is gone with it). Document the bound in the rt-link.yaml netlink spec. 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): ip link add v0 txqueuelen 500000 type veth peer name v1 -> on the fixed kernel this is rejected with -ERANGE ("integer out of range" extack) instead of installing an oversized tx_queue_len that later inflates pfifo_fast/tun/tap ring allocati

Announced Source revision 1
Original source ↗

CVE-2026-98021

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-98021

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "38f7b870d4a6a5d3ec21557e849620cb7d032965",
        "lessThan": "26ee5f99ffe7ab98e635071290eff14192e9e34a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "38f7b870d4a6a5d3ec21557e849620cb7d032965",
        "lessThan": "45ca9f59b6c7ea70e0a17054902b8a556913db34",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "38f7b870d4a6a5d3ec21557e849620cb7d032965",
        "lessThan": "2fd0880f0272ec022906a05587fd91416ebecc38",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "38f7b870d4a6a5d3ec21557e849620cb7d032965",
        "lessThan": "a638a2625aa83160a394abe8e8b2e524a80c771b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "38f7b870d4a6a5d3ec21557e849620cb7d032965",
        "lessThan": "1aa9e143bf51405665a793d4cc925e1c4f0c5922",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "Documentation/netlink/specs/rt-link.yaml",
      "net/core/rtnetlink.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.23"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.23",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "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": "*"
      }
    ],
    "programFiles": [
      "Documentation/netlink/specs/rt-link.yaml",
      "net/core/rtnetlink.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98021

Source reference: /cveMetadata/cveId

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No explicit severity was provided.

Event
#48829 · Revision 1
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