Vulnerability-Lookup

GHSA-GVVQ-54CJ-7XG4

Vulnerability from github – Published: 2026-10-18 18:31 – Updated: 2026-10-18 18:31

Details

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.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98596"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-18T16:17:12Z",
    "severity": null
  },
  "details": "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": "GHSA-gvvq-54cj-7xg4",
  "modified": "2026-10-18T18:31:55Z",
  "published": "2026-10-18T18:31:55Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98596"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5045aa25f3790dcdb158a58ac60ccf8da42959aa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/be31fe6333f534155e6b408f1ef6d77974bb41aa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ed902d5546fb9c142b3216d8eec914fa1bc0aa80"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f9722746df13a8a29103c847ef56b02c11ce0963"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-98596 (GCVE-0-2026-98596)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:19 – Updated: 2026-10-19 09:22

Title

ipv6: Fix dst leak for uncached routes.

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.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7018 records in the last 180 days details

References

4 references

URL	Tags
https://git.kernel.org/stable/c/5045aa25f3790dcdb…
https://git.kernel.org/stable/c/ed902d5546fb9c142…
https://git.kernel.org/stable/c/f9722746df13a8a29…
https://git.kernel.org/stable/c/be31fe6333f534155…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 98aa546af5e4f180439c82da403cc77926d3953b , < 5045aa25f3790dcdb158a58ac60ccf8da42959aa (git) Affected: 98aa546af5e4f180439c82da403cc77926d3953b , < ed902d5546fb9c142b3216d8eec914fa1bc0aa80 (git) Affected: 98aa546af5e4f180439c82da403cc77926d3953b , < f9722746df13a8a29103c847ef56b02c11ce0963 (git) Affected: 98aa546af5e4f180439c82da403cc77926d3953b , < be31fe6333f534155e6b408f1ef6d77974bb41aa (git)
Linux	Linux	Affected: 6.11 Unaffected: 0 , < 6.11 (semver) Unaffected: 6.12.112 , ≤ 6.12.* (semver) Unaffected: 6.18.55 , ≤ 6.18.* (semver) Unaffected: 7.2.9 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "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",
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          "versions": [
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              "lessThan": "5045aa25f3790dcdb158a58ac60ccf8da42959aa",
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              "versionType": "git"
            },
            {
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              "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": [
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            "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"
            },
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              "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.112",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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          "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."
        }
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        "dateUpdated": "2026-10-19T09:22:21.750Z",
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    "datePublished": "2026-10-18T15:19:09.189Z",
    "dateReserved": "2026-09-25T10:25:14.359Z",
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    "state": "PUBLISHED"
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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