GHSA-2GH3-WM75-4Q8M

Vulnerability from github – Published: 2026-04-25 09:30 – Updated: 2026-04-27 15:30
VLAI?
Details

In the Linux kernel, the following vulnerability has been resolved:

net/sched: sch_netem: fix out-of-bounds access in packet corruption

In netem_enqueue(), the packet corruption logic uses get_random_u32_below(skb_headlen(skb)) to select an index for modifying skb->data. When an AF_PACKET TX_RING sends fully non-linear packets over an IPIP tunnel, skb_headlen(skb) evaluates to 0.

Passing 0 to get_random_u32_below() takes the variable-ceil slow path which returns an unconstrained 32-bit random integer. Using this unconstrained value as an offset into skb->data results in an out-of-bounds memory access.

Fix this by verifying skb_headlen(skb) is non-zero before attempting to corrupt the linear data area. Fully non-linear packets will silently bypass the corruption logic.

Severity ?
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-31675"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-125"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-25T09:16:01Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_netem: fix out-of-bounds access in packet corruption\n\nIn netem_enqueue(), the packet corruption logic uses\nget_random_u32_below(skb_headlen(skb)) to select an index for\nmodifying skb-\u003edata. When an AF_PACKET TX_RING sends fully non-linear\npackets over an IPIP tunnel, skb_headlen(skb) evaluates to 0.\n\nPassing 0 to get_random_u32_below() takes the variable-ceil slow path\nwhich returns an unconstrained 32-bit random integer. Using this\nunconstrained value as an offset into skb-\u003edata results in an\nout-of-bounds memory access.\n\nFix this by verifying skb_headlen(skb) is non-zero before attempting\nto corrupt the linear data area. Fully non-linear packets will silently\nbypass the corruption logic.",
  "id": "GHSA-2gh3-wm75-4q8m",
  "modified": "2026-04-27T15:30:50Z",
  "published": "2026-04-25T09:30:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31675"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/13a66ca1e235d4bcd53d12d4c68490cad7f8e46f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3a2999704ac36cfb4041fed3652d26a3373e8d12"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4fd258e281fa8bc15e9ce2c7691941537e9258ad"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a14b56863348686dd0387eea8ce66b85cf455908"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d64cb81dcbd54927515a7f65e5e24affdc73c14b"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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