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net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes Reject invalid `net.ipv4.tcp_reordering` values before they reach TCP socket state. The sysctl is stored as an `int` but copied into the `u32` `tp->reordering` field for new sockets, so negative writes wrap to large values. With `tcp_mtu_probing=2`, the wrapped value can overflow the `tcp_mtu_probe()` size calculation and drive the MTU probing path into an out-of-bounds read. Route `tcp_reordering` writes through `proc_dointvec_minmax()` and require it to be at least 1. Also require `tcp_max_reordering` to be at least 1 so the configured maximum cannot become negative either. When registering the table for a non-init network namespace, relocate `extra2` pointers that refer into `init_net.ipv4` so the `tcp_reordering` upper bound follows that namespace's `tcp_max_reordering`. Harden `tcp_mtu_probe()` itself by computing `size_needed` as `u64`. This keeps the send queue and window checks from being bypassed through signed integer overflow.

Announced Source revision 1
Original source ↗

CVE-2026-64422

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-2026-64422

Linux

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

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

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": "91cc17c0e5e5ada156a8d5787a2509d263ea6bbf",
        "lessThan": "f0d88a4cd03affff6c08adf6c63964e235aede43",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "91cc17c0e5e5ada156a8d5787a2509d263ea6bbf",
        "lessThan": "27ddf4486c7dbf5bdd393fa8bef6b67179796d98",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "91cc17c0e5e5ada156a8d5787a2509d263ea6bbf",
        "lessThan": "782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "91cc17c0e5e5ada156a8d5787a2509d263ea6bbf",
        "lessThan": "e81f805824a8109504fce090641b17d135b48cd1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "91cc17c0e5e5ada156a8d5787a2509d263ea6bbf",
        "lessThan": "99206ce2244f8a3ed64298d0667c9055845a5dc7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "91cc17c0e5e5ada156a8d5787a2509d263ea6bbf",
        "lessThan": "bbae351c0f32f7c200249e4aa6561b2b419dcf69",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "91cc17c0e5e5ada156a8d5787a2509d263ea6bbf",
        "lessThan": "a094ac95d3b69adfa1676eb9c8eae6835d4f1671",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "91cc17c0e5e5ada156a8d5787a2509d263ea6bbf",
        "lessThan": "efb8763d7bbb40cff4cc55a6b62c3095a038149c",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/ipv4/sysctl_net_ipv4.c",
      "net/ipv4/tcp_output.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.24"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.24",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.261",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.212",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.178",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.145",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.96",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.39",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.4",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/ipv4/sysctl_net_ipv4.c",
      "net/ipv4/tcp_output.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-64422

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#41038 · Revision 1
Added to Heist Feed
Publisher date
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