GHSA-5WP9-X843-XMXF

Vulnerability from github – Published: 2026-06-25 09:31 – Updated: 2026-06-25 09:31
VLAI
Details

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

netfilter: nft_fib: fix stale stack leak via the OIFNAME register

For NFT_FIB_RESULT_OIFNAME the destination register is declared with len = IFNAMSIZ (four 32-bit registers), but on the lookup-fail, RTN_LOCAL and oif-mismatch paths nft_fib{4,6}_eval() only writes one register via "*dest = 0". The remaining three registers are left as whatever was on the stack in nft_do_chain()'s struct nft_regs, and a downstream expression that loads the register span can leak that uninitialised kernel stack to userspace.

The NFTA_FIB_F_PRESENT existence check has the same shape: it is only meaningful for NFT_FIB_RESULT_OIF, yet it was accepted for any result type while the eval stores a single byte via nft_reg_store8(), leaving the rest of the declared span stale.

Fix both:

  • replace the bare "*dest = 0" in the eval with nft_fib_store_result(), which strscpy_pad()s the whole IFNAMSIZ for OIFNAME (and is already used on the other early-return path), and

  • restrict NFTA_FIB_F_PRESENT to NFT_FIB_RESULT_OIF and declare its destination as a single u8, so the marked span matches the one byte the eval writes.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-53134"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-25T09:16:30Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_fib: fix stale stack leak via the OIFNAME register\n\nFor NFT_FIB_RESULT_OIFNAME the destination register is declared with\nlen = IFNAMSIZ (four 32-bit registers), but on the lookup-fail,\nRTN_LOCAL and oif-mismatch paths nft_fib{4,6}_eval() only writes one\nregister via \"*dest = 0\". The remaining three registers are left as\nwhatever was on the stack in nft_do_chain()\u0027s struct nft_regs, and a\ndownstream expression that loads the register span can leak that\nuninitialised kernel stack to userspace.\n\nThe NFTA_FIB_F_PRESENT existence check has the same shape: it is only\nmeaningful for NFT_FIB_RESULT_OIF, yet it was accepted for any result type\nwhile the eval stores a single byte via nft_reg_store8(), leaving the rest\nof the declared span stale.\n\nFix both:\n\n - replace the bare \"*dest = 0\" in the eval with nft_fib_store_result(),\n   which strscpy_pad()s the whole IFNAMSIZ for OIFNAME (and is already\n   used on the other early-return path), and\n\n - restrict NFTA_FIB_F_PRESENT to NFT_FIB_RESULT_OIF and declare its\n   destination as a single u8, so the marked span matches the one byte\n   the eval writes.",
  "id": "GHSA-5wp9-x843-xmxf",
  "modified": "2026-06-25T09:31:18Z",
  "published": "2026-06-25T09:31:18Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53134"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3544210609f6d1db282bbdeca639104ef624c393"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6744e49fe51bfba26522acc2d0e9703cb41d8e50"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/84d8f58cf28a0415413f43ba7148f7bacd4c1b6e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8c84885e9790823828bb8084736ea15769b1ac16"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ab185e0c4fb82dfba6fb86f8271e06f931d9c64c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d19ddef8c327a4773ff81f8e51027d1e0b4cf069"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eb8a8124484dbc3c2b543e207da39bbccb703d31"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eca18feed38b3377a2ec5d1f22af1170c55d0171"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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