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FKIE_CVE-2026-72392

Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-19 17:21
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv6: fib6: fix NULL deref in fib6_walk_continue() on multi-batch dump inet6_dump_fib() saves its progress in cb->args[1] as a positional index within the current hash chain. Between batches, a concurrent fib6_new_table() can insert a new table at the chain head, shifting all existing entries. The saved index then lands on a different table, causing fib6_dump_table() to set w->root to the wrong table while w->node still points into the previous one. fib6_walk_continue() dereferences w->node->parent (NULL) and panics: BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: 0010:fib6_walk_continue+0x6e/0x170 Call Trace: <TASK> fib6_dump_table.isra.0+0xc5/0x240 inet6_dump_fib+0xf6/0x420 rtnl_dumpit+0x30/0xa0 netlink_dump+0x15b/0x460 netlink_recvmsg+0x1d6/0x2a0 ____sys_recvmsg+0x17a/0x190 Fix by storing tb->tb6_id in cb->args[1] instead of a positional index. On resume, skip entries until the id matches; a concurrent head-insert can never match the saved id, so the walker always resumes on the correct table.
Impacted products
Vendor Product Version

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/ip6_fib.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ee73a32dd258d4af66831ff006b771e19812b322",
              "status": "affected",
              "version": "1b43af5480c351dbcb2eef478bafe179cbeb6e83",
              "versionType": "git"
            },
            {
              "lessThan": "89f9c5fee3c64c5cabc34e65599308fd3c879cf9",
              "status": "affected",
              "version": "1b43af5480c351dbcb2eef478bafe179cbeb6e83",
              "versionType": "git"
            },
            {
              "lessThan": "cb90a774a9c6c46961a44949a246fbb61f5f934c",
              "status": "affected",
              "version": "1b43af5480c351dbcb2eef478bafe179cbeb6e83",
              "versionType": "git"
            },
            {
              "lessThan": "27210d433a8c5fe6bf7278a04bbaeb49a81d0290",
              "status": "affected",
              "version": "1b43af5480c351dbcb2eef478bafe179cbeb6e83",
              "versionType": "git"
            },
            {
              "lessThan": "059efb48dd746518898faaa9b965511009b59639",
              "status": "affected",
              "version": "1b43af5480c351dbcb2eef478bafe179cbeb6e83",
              "versionType": "git"
            },
            {
              "lessThan": "d8a01d27873e04bebd357dc87859aa756e0b28b2",
              "status": "affected",
              "version": "1b43af5480c351dbcb2eef478bafe179cbeb6e83",
              "versionType": "git"
            },
            {
              "lessThan": "110ccbd28c9444866fcc84ba96a2ad64fa6e95ae",
              "status": "affected",
              "version": "1b43af5480c351dbcb2eef478bafe179cbeb6e83",
              "versionType": "git"
            },
            {
              "lessThan": "9facb861dc6b9b9ea9793ef5032a9a826f7a4229",
              "status": "affected",
              "version": "1b43af5480c351dbcb2eef478bafe179cbeb6e83",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/ip6_fib.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.19"
            },
            {
              "lessThan": "2.6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.151",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: fib6: fix NULL deref in fib6_walk_continue() on multi-batch dump\n\ninet6_dump_fib() saves its progress in cb-\u003eargs[1] as a positional\nindex within the current hash chain.  Between batches, a concurrent\nfib6_new_table() can insert a new table at the chain head, shifting\nall existing entries.  The saved index then lands on a different\ntable, causing fib6_dump_table() to set w-\u003eroot to the wrong table\nwhile w-\u003enode still points into the previous one.\nfib6_walk_continue() dereferences w-\u003enode-\u003eparent (NULL) and panics:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000008\n  RIP: 0010:fib6_walk_continue+0x6e/0x170\n  Call Trace:\n   \u003cTASK\u003e\n   fib6_dump_table.isra.0+0xc5/0x240\n   inet6_dump_fib+0xf6/0x420\n   rtnl_dumpit+0x30/0xa0\n   netlink_dump+0x15b/0x460\n   netlink_recvmsg+0x1d6/0x2a0\n   ____sys_recvmsg+0x17a/0x190\n\nFix by storing tb-\u003etb6_id in cb-\u003eargs[1] instead of a positional\nindex.  On resume, skip entries until the id matches; a concurrent\nhead-insert can never match the saved id, so the walker always\nresumes on the correct table."
    }
  ],
  "id": "CVE-2026-72392",
  "lastModified": "2026-08-19T17:21:00.820",
  "metrics": {},
  "published": "2026-08-15T06:22:12.733",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/059efb48dd746518898faaa9b965511009b59639"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/110ccbd28c9444866fcc84ba96a2ad64fa6e95ae"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/27210d433a8c5fe6bf7278a04bbaeb49a81d0290"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/89f9c5fee3c64c5cabc34e65599308fd3c879cf9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9facb861dc6b9b9ea9793ef5032a9a826f7a4229"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cb90a774a9c6c46961a44949a246fbb61f5f934c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d8a01d27873e04bebd357dc87859aa756e0b28b2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ee73a32dd258d4af66831ff006b771e19812b322"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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