CVE-2026-64580 (GCVE-0-2026-64580)
Vulnerability from cvelistv5
Published
2026-08-05 08:09
Modified
2026-08-19 16:29
Summary
In the Linux kernel, the following vulnerability has been resolved: xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst() On the error path where in6_dev_get(dev) returns NULL, xfrm6_fill_dst() releases the device reference with netdev_put() but leaves xdst->u.dst.dev set. dst_destroy() later calls netdev_put(dst->dev) again, so the same net_device reference is released twice, underflowing its refcount (ref_tracker WARNING + "unregister_netdevice: waiting for <dev> to become free"). Clear xdst->u.dst.dev after the netdev_put(), the same way the XFRM device-offload paths xfrm_dev_state_add() and xfrm_dev_policy_add() in net/xfrm/xfrm_device.c NULL ->dev when releasing the reference on error. ref_tracker: reference already released. ref_tracker: allocated in: xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:86) ... udpv6_sendmsg (net/ipv6/udp.c:1696) ... ref_tracker: freed in: xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:90) ... WARNING: lib/ref_tracker.c:322 at ref_tracker_free+0x58b/0x780 dst_destroy (net/core/dst.c:115) rcu_core handle_softirqs ...
Impacted products
Vendor Product Version
Linux Linux Version: 84c4a9dfbf430861e7588d95ae3ff61535dca351
Version: 84c4a9dfbf430861e7588d95ae3ff61535dca351
Version: 84c4a9dfbf430861e7588d95ae3ff61535dca351
Version: 84c4a9dfbf430861e7588d95ae3ff61535dca351
Version: 84c4a9dfbf430861e7588d95ae3ff61535dca351
Version: 84c4a9dfbf430861e7588d95ae3ff61535dca351
Version: a7e22d0c0e81dde129a51ee413644124f4b59954
Version: 01b0d887f67a388fb2a658ee2bdd74e5ba146818
Version: a98124aac0b5adc5de8ae54f11322781cb4d85c3
Version: e27b7bee743d921f037b1da6f071237345bef7c1
Version: 3.0.79   
Version: 3.2.46   
Version: 3.4.46   
Version: 3.9.3   
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{
  "containers": {
    "cna": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/xfrm6_policy.c"
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              "status": "affected",
              "version": "3.9.3",
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          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/xfrm6_policy.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "3.10"
            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "version": "6.1.183",
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              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.148",
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            },
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              "status": "unaffected",
              "version": "6.12.101",
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            },
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              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
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            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
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            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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                  "versionStartIncluding": "3.10",
                  "vulnerable": true
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                  "versionEndExcluding": "6.6.148",
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                  "vulnerable": true
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                  "vulnerable": true
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                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "3.10",
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                },
                {
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                },
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()\n\nOn the error path where in6_dev_get(dev) returns NULL, xfrm6_fill_dst()\nreleases the device reference with netdev_put() but leaves\nxdst-\u003eu.dst.dev set. dst_destroy() later calls netdev_put(dst-\u003edev)\nagain, so the same net_device reference is released twice, underflowing\nits refcount (ref_tracker WARNING + \"unregister_netdevice: waiting for\n\u003cdev\u003e to become free\").\n\nClear xdst-\u003eu.dst.dev after the netdev_put(), the same way the XFRM\ndevice-offload paths xfrm_dev_state_add() and xfrm_dev_policy_add() in\nnet/xfrm/xfrm_device.c NULL -\u003edev when releasing the reference on error.\n\n  ref_tracker: reference already released.\n  ref_tracker: allocated in:\n   xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:86)\n   ...\n   udpv6_sendmsg (net/ipv6/udp.c:1696)\n   ...\n  ref_tracker: freed in:\n   xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:90)\n   ...\n  WARNING: lib/ref_tracker.c:322 at ref_tracker_free+0x58b/0x780\n   dst_destroy (net/core/dst.c:115)\n   rcu_core\n   handle_softirqs\n   ..."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached on the local IPv6 outbound path (udpv6_sendmsg \u2192 xfrm_lookup \u2192 xfrm6_fill_dst) after configuring XFRM policy/state via netlink or IPV6_XFRM_POLICY; a remote peer cannot drive that configuration or the device state that makes in6_dev_get fail.\nAC:L - An attacker in their own netns can create interfaces, install IPv6 XFRM policy/state, generate matching UDP traffic, and concurrently drop MTU below IPV6_MIN_MTU or unregister the device to clear ip6_ptr, so they control both sides of the window that hits the error path; once entered, the double netdev_put is deterministic.\nPR:L - XFRM configuration requires CAP_NET_ADMIN via netlink_net_capable/sockopt_ns_capable, which is ns_capable() in the netns user_ns, so an unprivileged user obtains it with unshare -Urn rather than real init-namespace root.\nUI:N - No victim action is required; the attacker configures XFRM, manipulates their own netdevs, and sends packets entirely with their own processes.\nS:U - The impact is kernel net_device refcount corruption within the same host kernel authority; this is ordinary local privilege-escalation/DoS territory, not a VM escape or IOMMU/sandbox boundary cross.\nC:H - The leftover dst.dev causes a second netdev_put in dst_destroy, underflowing the net_device refcount and enabling use-after-free of the device object, which per kernel UAF guidance yields a high confidentiality/info-disclosure primitive.\nI:H - A net_device refcount underflow/UAF is heap memory corruption that can be shaped via reuse/spraying into arbitrary write or control-flow hijack, so integrity impact is high.\nA:H - Even without full exploitation, the double put triggers ref_tracker warnings and can oops/panic or hang device unregister (unregister_netdevice waiting for the device to become free), so availability impact is high."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:29:07.038Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/97e032e5733e49471fb73de117ea2ac1ac7c479a"
        },
        {
          "url": "https://git.kernel.org/stable/c/df6856c2dda9187601d29b5fbd7a81b3b178cedf"
        },
        {
          "url": "https://git.kernel.org/stable/c/43de8a49335e611adb271bbd52e84dfbc11fc185"
        },
        {
          "url": "https://git.kernel.org/stable/c/ff636d7b7cba6dea82ecf580415ea57f2c1a11b6"
        },
        {
          "url": "https://git.kernel.org/stable/c/e078da1b4e11390cff3201c19a9a1fe70c5b934f"
        },
        {
          "url": "https://git.kernel.org/stable/c/136992de9bb91871084ae52d172610541c76e4d2"
        }
      ],
      "title": "xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64580",
    "datePublished": "2026-08-05T08:09:34.946Z",
    "dateReserved": "2026-07-19T15:36:31.798Z",
    "dateUpdated": "2026-08-19T16:29:07.038Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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