FKIE_CVE-2026-98596

Vulnerability from fkie_nvd - Published: 2026-10-18 16:17 - Updated: 2026-10-19 10:19
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv6: Fix dst leak for uncached routes. ip6_route_output_flags(), ip6_rt_put_flags(), and ip6_dst_check() detect an uncached route by list_empty(&rt->dst.rt_uncached), which replaced the static DST_NOCACHE flag check in commit a4c2fd7f7891 ("net: remove DST_NOCACHE flag"). When a device is unregistered, rt6_uncached_list_flush_dev() unlinks uncached routes tied to the device from rt6_uncached_list. Previously, they were moved to another list with list_move() (__list_del_entry() + list_add()), and since commit 98aa546af5e4 ("inet: remove (struct uncached_list)->quarantine"), the routes are just unlinked with list_del_init(). If list_del_init() runs concurrently, list_empty() evaluates to true; ip6_route_output_flags() calls dst_hold_safe() incorrectly and ip6_rt_put_flags() skips ip6_rt_put(), leaking dst, and thus dev tied via rt->from as well. The same race is partially fixed by commit 9a6f0c4d5796 ("dst: fix races in rt6_uncached_list_del() and rt_del_uncached_list()"). Let's check rt6->dst.rt_uncached_list instead. Note that IPv4 does not have the same issue.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5045aa25f3790dcdb158a58ac60ccf8da42959aa
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/be31fe6333f534155e6b408f1ef6d77974bb41aa
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ed902d5546fb9c142b3216d8eec914fa1bc0aa80
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f9722746df13a8a29103c847ef56b02c11ce0963
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/net/ip6_route.h",
            "net/ipv6/route.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5045aa25f3790dcdb158a58ac60ccf8da42959aa",
              "status": "affected",
              "version": "98aa546af5e4f180439c82da403cc77926d3953b",
              "versionType": "git"
            },
            {
              "lessThan": "ed902d5546fb9c142b3216d8eec914fa1bc0aa80",
              "status": "affected",
              "version": "98aa546af5e4f180439c82da403cc77926d3953b",
              "versionType": "git"
            },
            {
              "lessThan": "f9722746df13a8a29103c847ef56b02c11ce0963",
              "status": "affected",
              "version": "98aa546af5e4f180439c82da403cc77926d3953b",
              "versionType": "git"
            },
            {
              "lessThan": "be31fe6333f534155e6b408f1ef6d77974bb41aa",
              "status": "affected",
              "version": "98aa546af5e4f180439c82da403cc77926d3953b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/net/ip6_route.h",
            "net/ipv6/route.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.55",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "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: Fix dst leak for uncached routes.\n\nip6_route_output_flags(), ip6_rt_put_flags(), and ip6_dst_check()\ndetect an uncached route by list_empty(\u0026rt-\u003edst.rt_uncached),\nwhich replaced the static DST_NOCACHE flag check in commit\na4c2fd7f7891 (\"net: remove DST_NOCACHE flag\").\n\nWhen a device is unregistered, rt6_uncached_list_flush_dev()\nunlinks uncached routes tied to the device from rt6_uncached_list.\n\nPreviously, they were moved to another list with list_move()\n(__list_del_entry() + list_add()), and since commit 98aa546af5e4\n(\"inet: remove (struct uncached_list)-\u003equarantine\"), the routes\nare just unlinked with list_del_init().\n\nIf list_del_init() runs concurrently, list_empty() evaluates to\ntrue; ip6_route_output_flags() calls dst_hold_safe() incorrectly\nand ip6_rt_put_flags() skips ip6_rt_put(), leaking dst, and thus\ndev tied via rt-\u003efrom as well.\n\nThe same race is partially fixed by commit 9a6f0c4d5796 (\"dst:\nfix races in rt6_uncached_list_del() and rt_del_uncached_list()\").\n\nLet\u0027s check rt6-\u003edst.rt_uncached_list instead.\n\nNote that IPv4 does not have the same issue."
    }
  ],
  "id": "CVE-2026-98596",
  "lastModified": "2026-10-19T10:19:20.913",
  "metrics": {},
  "published": "2026-10-18T16:17:12.283",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5045aa25f3790dcdb158a58ac60ccf8da42959aa"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/be31fe6333f534155e6b408f1ef6d77974bb41aa"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ed902d5546fb9c142b3216d8eec914fa1bc0aa80"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f9722746df13a8a29103c847ef56b02c11ce0963"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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