GHSA-GWMG-Q555-3325

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-10-15 03:36
VLAI
Details

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.

Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-64422"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-190"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:26Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv4: bound TCP reordering sysctl writes and MTU probe sizes\n\nReject invalid `net.ipv4.tcp_reordering` values before they reach TCP\nsocket state. The sysctl is stored as an `int` but copied into the\n`u32` `tp-\u003ereordering` field for new sockets, so negative writes wrap\nto large values.\n\nWith `tcp_mtu_probing=2`, the wrapped value can overflow the\n`tcp_mtu_probe()` size calculation and drive the MTU probing path into\nan out-of-bounds read. Route `tcp_reordering` writes through\n`proc_dointvec_minmax()` and require it to be at least 1. Also require\n`tcp_max_reordering` to be at least 1 so the configured maximum cannot\nbecome negative either.\n\nWhen registering the table for a non-init network namespace, relocate\n`extra2` pointers that refer into `init_net.ipv4` so the\n`tcp_reordering` upper bound follows that namespace\u0027s\n`tcp_max_reordering`.\n\nHarden `tcp_mtu_probe()` itself by computing `size_needed` as `u64`.\nThis keeps the send queue and window checks from being bypassed through\nsigned integer overflow.",
  "id": "GHSA-gwmg-q555-3325",
  "modified": "2026-10-15T03:36:21Z",
  "published": "2026-07-25T12:31:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64422"
    },
    {
      "type": "WEB",
      "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
    },
    {
      "type": "WEB",
      "url": "https://cert-portal.siemens.com/productcert/html/ssa-457936.html"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/27ddf4486c7dbf5bdd393fa8bef6b67179796d98"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/99206ce2244f8a3ed64298d0667c9055845a5dc7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a094ac95d3b69adfa1676eb9c8eae6835d4f1671"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bbae351c0f32f7c200249e4aa6561b2b419dcf69"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e81f805824a8109504fce090641b17d135b48cd1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/efb8763d7bbb40cff4cc55a6b62c3095a038149c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f0d88a4cd03affff6c08adf6c63964e235aede43"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.