Vulnerability-Lookup

GHSA-C37C-FRR8-RX54

Vulnerability from github – Published: 2026-07-27 21:31 – Updated: 2026-07-27 21:31

Details

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

ipv6: Fix null-ptr-deref in fib6_nh_mtu_change().

fib6_nh_mtu_change() re-fetches idev via __in6_dev_get(arg->dev) and dereferences idev->cnf.mtu6 without a NULL check. addrconf_ifdown() clears dev->ip6_ptr with RCU_INIT_POINTER() after rt6_disable_ip() has released tb6_lock, so the RA-driven MTU walk can observe a NULL idev and oops. The caller rt6_mtu_change_route() guards its own __in6_dev_get(), but this re-fetch is unguarded; nexthop-backed routes survive addrconf_ifdown()'s flush, so the walk still reaches it after ip6_ptr is nulled.

Return 0 when idev is NULL, matching rt6_mtu_change_route() and the fib6_mtu() fix in commit 5ad509c1fdad ("ipv6: Fix null-ptr-deref in fib6_mtu().").

Oops: general protection fault, ... KASAN: null-ptr-deref in range [0x00000000000002a8-0x00000000000002af] RIP: 0010:fib6_nh_mtu_change+0x203/0x990 rt6_mtu_change_route+0x141/0x1d0 __fib6_clean_all+0xd0/0x160 rt6_mtu_change+0xb4/0x100 ndisc_router_discovery+0x24b5/0x2cb0 icmpv6_rcv+0x12e9/0x1710 ipv6_rcv+0x39b/0x410

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-64538"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-27T21:17:06Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: Fix null-ptr-deref in fib6_nh_mtu_change().\n\nfib6_nh_mtu_change() re-fetches idev via __in6_dev_get(arg-\u003edev) and\ndereferences idev-\u003ecnf.mtu6 without a NULL check. addrconf_ifdown()\nclears dev-\u003eip6_ptr with RCU_INIT_POINTER() after rt6_disable_ip() has\nreleased tb6_lock, so the RA-driven MTU walk can observe a NULL idev and\noops. The caller rt6_mtu_change_route() guards its own __in6_dev_get(),\nbut this re-fetch is unguarded; nexthop-backed routes survive\naddrconf_ifdown()\u0027s flush, so the walk still reaches it after ip6_ptr is\nnulled.\n\nReturn 0 when idev is NULL, matching rt6_mtu_change_route() and the\nfib6_mtu() fix in commit 5ad509c1fdad (\"ipv6: Fix null-ptr-deref in\nfib6_mtu().\").\n\n  Oops: general protection fault, ... KASAN: null-ptr-deref in range\n        [0x00000000000002a8-0x00000000000002af]\n  RIP: 0010:fib6_nh_mtu_change+0x203/0x990\n   rt6_mtu_change_route+0x141/0x1d0\n   __fib6_clean_all+0xd0/0x160\n   rt6_mtu_change+0xb4/0x100\n   ndisc_router_discovery+0x24b5/0x2cb0\n   icmpv6_rcv+0x12e9/0x1710\n   ipv6_rcv+0x39b/0x410",
  "id": "GHSA-c37c-frr8-rx54",
  "modified": "2026-07-27T21:31:26Z",
  "published": "2026-07-27T21:31:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64538"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1451deca9896957159f0666520a792c1b861af4f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/302d57ed7872838b40e56a868fb4c7da7da606e9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/46c3b8191aad3d032776bf3bebf03efdf5f4b905"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6428634f7a0b7878144b4925c37856bef3224967"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/80600b5d0f3ecb9324120dc95b5e915130f516c5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b0d0eb13a0441a8ebf4f227843deaf494f1e2c33"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b2c70dd3326809429b709a9c7e9220d29923051a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d08d019f2f43a6f9a71e81868bbc326b3afaf37b"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-64538 (GCVE-0-2026-64538)

Vulnerability from cvelistv5 – Published: 2026-07-27 20:10 – Updated: 2026-07-27 20:10

Title

ipv6: Fix null-ptr-deref in fib6_nh_mtu_change().

Summary

In the Linux kernel, the following vulnerability has been resolved: ipv6: Fix null-ptr-deref in fib6_nh_mtu_change(). fib6_nh_mtu_change() re-fetches idev via __in6_dev_get(arg->dev) and dereferences idev->cnf.mtu6 without a NULL check. addrconf_ifdown() clears dev->ip6_ptr with RCU_INIT_POINTER() after rt6_disable_ip() has released tb6_lock, so the RA-driven MTU walk can observe a NULL idev and oops. The caller rt6_mtu_change_route() guards its own __in6_dev_get(), but this re-fetch is unguarded; nexthop-backed routes survive addrconf_ifdown()'s flush, so the walk still reaches it after ip6_ptr is nulled. Return 0 when idev is NULL, matching rt6_mtu_change_route() and the fib6_mtu() fix in commit 5ad509c1fdad ("ipv6: Fix null-ptr-deref in fib6_mtu()."). Oops: general protection fault, ... KASAN: null-ptr-deref in range [0x00000000000002a8-0x00000000000002af] RIP: 0010:fib6_nh_mtu_change+0x203/0x990 rt6_mtu_change_route+0x141/0x1d0 __fib6_clean_all+0xd0/0x160 rt6_mtu_change+0xb4/0x100 ndisc_router_discovery+0x24b5/0x2cb0 icmpv6_rcv+0x12e9/0x1710 ipv6_rcv+0x39b/0x410

Severity

No CVSS data available.

Assigner

Linux

References

8 references

URL	Tags
https://git.kernel.org/stable/c/d08d019f2f43a6f9a…
https://git.kernel.org/stable/c/1451deca989695715…
https://git.kernel.org/stable/c/b2c70dd3326809429…
https://git.kernel.org/stable/c/302d57ed7872838b4…
https://git.kernel.org/stable/c/80600b5d0f3ecb932…
https://git.kernel.org/stable/c/b0d0eb13a0441a8eb…
https://git.kernel.org/stable/c/6428634f7a0b78781…
https://git.kernel.org/stable/c/46c3b8191aad3d032…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c0b220cf7d80eb8a36ae9f12cae6df4577a6814e , < d08d019f2f43a6f9a71e81868bbc326b3afaf37b (git) Affected: c0b220cf7d80eb8a36ae9f12cae6df4577a6814e , < 1451deca9896957159f0666520a792c1b861af4f (git) Affected: c0b220cf7d80eb8a36ae9f12cae6df4577a6814e , < b2c70dd3326809429b709a9c7e9220d29923051a (git) Affected: c0b220cf7d80eb8a36ae9f12cae6df4577a6814e , < 302d57ed7872838b40e56a868fb4c7da7da606e9 (git) Affected: c0b220cf7d80eb8a36ae9f12cae6df4577a6814e , < 80600b5d0f3ecb9324120dc95b5e915130f516c5 (git) Affected: c0b220cf7d80eb8a36ae9f12cae6df4577a6814e , < b0d0eb13a0441a8ebf4f227843deaf494f1e2c33 (git) Affected: c0b220cf7d80eb8a36ae9f12cae6df4577a6814e , < 6428634f7a0b7878144b4925c37856bef3224967 (git) Affected: c0b220cf7d80eb8a36ae9f12cae6df4577a6814e , < 46c3b8191aad3d032776bf3bebf03efdf5f4b905 (git)
Linux	Linux	Affected: 5.3 Unaffected: 0 , < 5.3 (semver) Unaffected: 5.10.261 , ≤ 5.10.* (semver) Unaffected: 5.15.212 , ≤ 5.15.* (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/route.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d08d019f2f43a6f9a71e81868bbc326b3afaf37b",
              "status": "affected",
              "version": "c0b220cf7d80eb8a36ae9f12cae6df4577a6814e",
              "versionType": "git"
            },
            {
              "lessThan": "1451deca9896957159f0666520a792c1b861af4f",
              "status": "affected",
              "version": "c0b220cf7d80eb8a36ae9f12cae6df4577a6814e",
              "versionType": "git"
            },
            {
              "lessThan": "b2c70dd3326809429b709a9c7e9220d29923051a",
              "status": "affected",
              "version": "c0b220cf7d80eb8a36ae9f12cae6df4577a6814e",
              "versionType": "git"
            },
            {
              "lessThan": "302d57ed7872838b40e56a868fb4c7da7da606e9",
              "status": "affected",
              "version": "c0b220cf7d80eb8a36ae9f12cae6df4577a6814e",
              "versionType": "git"
            },
            {
              "lessThan": "80600b5d0f3ecb9324120dc95b5e915130f516c5",
              "status": "affected",
              "version": "c0b220cf7d80eb8a36ae9f12cae6df4577a6814e",
              "versionType": "git"
            },
            {
              "lessThan": "b0d0eb13a0441a8ebf4f227843deaf494f1e2c33",
              "status": "affected",
              "version": "c0b220cf7d80eb8a36ae9f12cae6df4577a6814e",
              "versionType": "git"
            },
            {
              "lessThan": "6428634f7a0b7878144b4925c37856bef3224967",
              "status": "affected",
              "version": "c0b220cf7d80eb8a36ae9f12cae6df4577a6814e",
              "versionType": "git"
            },
            {
              "lessThan": "46c3b8191aad3d032776bf3bebf03efdf5f4b905",
              "status": "affected",
              "version": "c0b220cf7d80eb8a36ae9f12cae6df4577a6814e",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/route.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.3"
            },
            {
              "lessThan": "5.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "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-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.261",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.212",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.178",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2-rc1",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: Fix null-ptr-deref in fib6_nh_mtu_change().\n\nfib6_nh_mtu_change() re-fetches idev via __in6_dev_get(arg-\u003edev) and\ndereferences idev-\u003ecnf.mtu6 without a NULL check. addrconf_ifdown()\nclears dev-\u003eip6_ptr with RCU_INIT_POINTER() after rt6_disable_ip() has\nreleased tb6_lock, so the RA-driven MTU walk can observe a NULL idev and\noops. The caller rt6_mtu_change_route() guards its own __in6_dev_get(),\nbut this re-fetch is unguarded; nexthop-backed routes survive\naddrconf_ifdown()\u0027s flush, so the walk still reaches it after ip6_ptr is\nnulled.\n\nReturn 0 when idev is NULL, matching rt6_mtu_change_route() and the\nfib6_mtu() fix in commit 5ad509c1fdad (\"ipv6: Fix null-ptr-deref in\nfib6_mtu().\").\n\n  Oops: general protection fault, ... KASAN: null-ptr-deref in range\n        [0x00000000000002a8-0x00000000000002af]\n  RIP: 0010:fib6_nh_mtu_change+0x203/0x990\n   rt6_mtu_change_route+0x141/0x1d0\n   __fib6_clean_all+0xd0/0x160\n   rt6_mtu_change+0xb4/0x100\n   ndisc_router_discovery+0x24b5/0x2cb0\n   icmpv6_rcv+0x12e9/0x1710\n   ipv6_rcv+0x39b/0x410"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-27T20:10:32.779Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d08d019f2f43a6f9a71e81868bbc326b3afaf37b"
        },
        {
          "url": "https://git.kernel.org/stable/c/1451deca9896957159f0666520a792c1b861af4f"
        },
        {
          "url": "https://git.kernel.org/stable/c/b2c70dd3326809429b709a9c7e9220d29923051a"
        },
        {
          "url": "https://git.kernel.org/stable/c/302d57ed7872838b40e56a868fb4c7da7da606e9"
        },
        {
          "url": "https://git.kernel.org/stable/c/80600b5d0f3ecb9324120dc95b5e915130f516c5"
        },
        {
          "url": "https://git.kernel.org/stable/c/b0d0eb13a0441a8ebf4f227843deaf494f1e2c33"
        },
        {
          "url": "https://git.kernel.org/stable/c/6428634f7a0b7878144b4925c37856bef3224967"
        },
        {
          "url": "https://git.kernel.org/stable/c/46c3b8191aad3d032776bf3bebf03efdf5f4b905"
        }
      ],
      "title": "ipv6: Fix null-ptr-deref in fib6_nh_mtu_change().",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64538",
    "datePublished": "2026-07-27T20:10:32.779Z",
    "dateReserved": "2026-07-19T15:36:31.795Z",
    "dateUpdated": "2026-07-27T20:10:32.779Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

GHSA-C37C-FRR8-RX54

CVE-2026-64538 (GCVE-0-2026-64538)

Tags

Sightings

Nomenclature