ghsa-96q9-fhgv-cmrv
Vulnerability from github
Published
2025-09-22 21:30
Modified
2025-09-22 21:30
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

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

net: ipv6: unexport __init-annotated seg6_hmac_init()

EXPORT_SYMBOL and __init is a bad combination because the .init.text section is freed up after the initialization. Hence, modules cannot use symbols annotated __init. The access to a freed symbol may end up with kernel panic.

modpost used to detect it, but it has been broken for a decade.

Recently, I fixed modpost so it started to warn it again, then this showed up in linux-next builds.

There are two ways to fix it:

  • Remove __init
  • Remove EXPORT_SYMBOL

I chose the latter for this case because the caller (net/ipv6/seg6.c) and the callee (net/ipv6/seg6_hmac.c) belong to the same module. It seems an internal function call in ipv6.ko.

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{
  "affected": [],
  "aliases": [
    "CVE-2022-49339"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-02-26T07:01:10Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv6: unexport __init-annotated seg6_hmac_init()\n\nEXPORT_SYMBOL and __init is a bad combination because the .init.text\nsection is freed up after the initialization. Hence, modules cannot\nuse symbols annotated __init. The access to a freed symbol may end up\nwith kernel panic.\n\nmodpost used to detect it, but it has been broken for a decade.\n\nRecently, I fixed modpost so it started to warn it again, then this\nshowed up in linux-next builds.\n\nThere are two ways to fix it:\n\n  - Remove __init\n  - Remove EXPORT_SYMBOL\n\nI chose the latter for this case because the caller (net/ipv6/seg6.c)\nand the callee (net/ipv6/seg6_hmac.c) belong to the same module.\nIt seems an internal function call in ipv6.ko.",
  "id": "GHSA-96q9-fhgv-cmrv",
  "modified": "2025-09-22T21:30:16Z",
  "published": "2025-09-22T21:30:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49339"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1084716f76c8045eadf92a9d9a62641f3c8d8c90"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/317260b3eb6384a05a8af212308fa50f3b2e8290"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3e6de5037148c5a93a436b1e8d2edad3dac11755"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5801f064e35181c71857a80ff18af4dbec3c5f5c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5d9c1b081ad28c852a97e10dd75412546497694a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/64aef8efe96c1616142c4476a05731306fc4494e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9ba4416b831eeb4d185e88e73488d1d21288e63a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ab8b2c2de273ec1d698a18e399896a6febb5cda0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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