CVE-2026-23209 (GCVE-0-2026-23209)

Vulnerability from cvelistv5 – Published: 2026-02-14 16:27 – Updated: 2026-02-14 16:27
VLAI?
Title
macvlan: fix error recovery in macvlan_common_newlink()
Summary
In the Linux kernel, the following vulnerability has been resolved: macvlan: fix error recovery in macvlan_common_newlink() valis provided a nice repro to crash the kernel: ip link add p1 type veth peer p2 ip link set address 00:00:00:00:00:20 dev p1 ip link set up dev p1 ip link set up dev p2 ip link add mv0 link p2 type macvlan mode source ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20 ping -c1 -I p1 1.2.3.4 He also gave a very detailed analysis: <quote valis> The issue is triggered when a new macvlan link is created with MACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or MACVLAN_MACADDR_SET) parameter, lower device already has a macvlan port and register_netdevice() called from macvlan_common_newlink() fails (e.g. because of the invalid link name). In this case macvlan_hash_add_source is called from macvlan_change_sources() / macvlan_common_newlink(): This adds a reference to vlan to the port's vlan_source_hash using macvlan_source_entry. vlan is a pointer to the priv data of the link that is being created. When register_netdevice() fails, the error is returned from macvlan_newlink() to rtnl_newlink_create(): if (ops->newlink) err = ops->newlink(dev, &params, extack); else err = register_netdevice(dev); if (err < 0) { free_netdev(dev); goto out; } and free_netdev() is called, causing a kvfree() on the struct net_device that is still referenced in the source entry attached to the lower device's macvlan port. Now all packets sent on the macvlan port with a matching source mac address will trigger a use-after-free in macvlan_forward_source(). </quote valis> With all that, my fix is to make sure we call macvlan_flush_sources() regardless of @create value whenever "goto destroy_macvlan_port;" path is taken. Many thanks to valis for following up on this issue.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: aa5fd0fb77486b8a6764ead8627baa14790e4280 , < da5c6b8ae47e414be47e5e04def15b25d5c962dc (git)
Affected: aa5fd0fb77486b8a6764ead8627baa14790e4280 , < 5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a (git)
Affected: aa5fd0fb77486b8a6764ead8627baa14790e4280 , < c43d0e787cbba569ec9d11579ed370b50fab6c9c (git)
Affected: aa5fd0fb77486b8a6764ead8627baa14790e4280 , < 11ba9f0dc865136174cb98834280fb21bbc950c7 (git)
Affected: aa5fd0fb77486b8a6764ead8627baa14790e4280 , < 986967a162142710076782d5b93daab93a892980 (git)
Affected: aa5fd0fb77486b8a6764ead8627baa14790e4280 , < cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66 (git)
Affected: aa5fd0fb77486b8a6764ead8627baa14790e4280 , < f8db6475a83649689c087a8f52486fcc53e627e9 (git)
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    Linux Linux Affected: 4.9
Unaffected: 0 , < 4.9 (semver)
Unaffected: 5.10.250 , ≤ 5.10.* (semver)
Unaffected: 5.15.200 , ≤ 5.15.* (semver)
Unaffected: 6.1.163 , ≤ 6.1.* (semver)
Unaffected: 6.6.124 , ≤ 6.6.* (semver)
Unaffected: 6.12.70 , ≤ 6.12.* (semver)
Unaffected: 6.18.10 , ≤ 6.18.* (semver)
Unaffected: 6.19 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/macvlan.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
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              "versionType": "git"
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          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/macvlan.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.9"
            },
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              "lessThan": "4.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.250",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.200",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.163",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.124",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.70",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.250",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.200",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.163",
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.124",
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.70",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.10",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
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          ]
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmacvlan: fix error recovery in macvlan_common_newlink()\n\nvalis provided a nice repro to crash the kernel:\n\nip link add p1 type veth peer p2\nip link set address 00:00:00:00:00:20 dev p1\nip link set up dev p1\nip link set up dev p2\n\nip link add mv0 link p2 type macvlan mode source\nip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20\n\nping -c1 -I p1 1.2.3.4\n\nHe also gave a very detailed analysis:\n\n\u003cquote valis\u003e\n\nThe issue is triggered when a new macvlan link is created  with\nMACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or\nMACVLAN_MACADDR_SET) parameter, lower device already has a macvlan\nport and register_netdevice() called from macvlan_common_newlink()\nfails (e.g. because of the invalid link name).\n\nIn this case macvlan_hash_add_source is called from\nmacvlan_change_sources() / macvlan_common_newlink():\n\nThis adds a reference to vlan to the port\u0027s vlan_source_hash using\nmacvlan_source_entry.\n\nvlan is a pointer to the priv data of the link that is being created.\n\nWhen register_netdevice() fails, the error is returned from\nmacvlan_newlink() to rtnl_newlink_create():\n\n        if (ops-\u003enewlink)\n                err = ops-\u003enewlink(dev, \u0026params, extack);\n        else\n                err = register_netdevice(dev);\n        if (err \u003c 0) {\n                free_netdev(dev);\n                goto out;\n        }\n\nand free_netdev() is called, causing a kvfree() on the struct\nnet_device that is still referenced in the source entry attached to\nthe lower device\u0027s macvlan port.\n\nNow all packets sent on the macvlan port with a matching source mac\naddress will trigger a use-after-free in macvlan_forward_source().\n\n\u003c/quote valis\u003e\n\nWith all that, my fix is to make sure we call macvlan_flush_sources()\nregardless of @create value whenever \"goto destroy_macvlan_port;\"\npath is taken.\n\nMany thanks to valis for following up on this issue."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-14T16:27:31.175Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/da5c6b8ae47e414be47e5e04def15b25d5c962dc"
        },
        {
          "url": "https://git.kernel.org/stable/c/5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a"
        },
        {
          "url": "https://git.kernel.org/stable/c/c43d0e787cbba569ec9d11579ed370b50fab6c9c"
        },
        {
          "url": "https://git.kernel.org/stable/c/11ba9f0dc865136174cb98834280fb21bbc950c7"
        },
        {
          "url": "https://git.kernel.org/stable/c/986967a162142710076782d5b93daab93a892980"
        },
        {
          "url": "https://git.kernel.org/stable/c/cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66"
        },
        {
          "url": "https://git.kernel.org/stable/c/f8db6475a83649689c087a8f52486fcc53e627e9"
        }
      ],
      "title": "macvlan: fix error recovery in macvlan_common_newlink()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23209",
    "datePublished": "2026-02-14T16:27:31.175Z",
    "dateReserved": "2026-01-13T15:37:45.986Z",
    "dateUpdated": "2026-02-14T16:27:31.175Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-23209\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-02-14T17:15:58.803\",\"lastModified\":\"2026-02-14T17:15:58.803\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmacvlan: fix error recovery in macvlan_common_newlink()\\n\\nvalis provided a nice repro to crash the kernel:\\n\\nip link add p1 type veth peer p2\\nip link set address 00:00:00:00:00:20 dev p1\\nip link set up dev p1\\nip link set up dev p2\\n\\nip link add mv0 link p2 type macvlan mode source\\nip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20\\n\\nping -c1 -I p1 1.2.3.4\\n\\nHe also gave a very detailed analysis:\\n\\n\u003cquote valis\u003e\\n\\nThe issue is triggered when a new macvlan link is created  with\\nMACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or\\nMACVLAN_MACADDR_SET) parameter, lower device already has a macvlan\\nport and register_netdevice() called from macvlan_common_newlink()\\nfails (e.g. because of the invalid link name).\\n\\nIn this case macvlan_hash_add_source is called from\\nmacvlan_change_sources() / macvlan_common_newlink():\\n\\nThis adds a reference to vlan to the port\u0027s vlan_source_hash using\\nmacvlan_source_entry.\\n\\nvlan is a pointer to the priv data of the link that is being created.\\n\\nWhen register_netdevice() fails, the error is returned from\\nmacvlan_newlink() to rtnl_newlink_create():\\n\\n        if (ops-\u003enewlink)\\n                err = ops-\u003enewlink(dev, \u0026params, extack);\\n        else\\n                err = register_netdevice(dev);\\n        if (err \u003c 0) {\\n                free_netdev(dev);\\n                goto out;\\n        }\\n\\nand free_netdev() is called, causing a kvfree() on the struct\\nnet_device that is still referenced in the source entry attached to\\nthe lower device\u0027s macvlan port.\\n\\nNow all packets sent on the macvlan port with a matching source mac\\naddress will trigger a use-after-free in macvlan_forward_source().\\n\\n\u003c/quote valis\u003e\\n\\nWith all that, my fix is to make sure we call macvlan_flush_sources()\\nregardless of @create value whenever \\\"goto destroy_macvlan_port;\\\"\\npath is taken.\\n\\nMany thanks to valis for following up on this issue.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/11ba9f0dc865136174cb98834280fb21bbc950c7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/986967a162142710076782d5b93daab93a892980\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c43d0e787cbba569ec9d11579ed370b50fab6c9c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/da5c6b8ae47e414be47e5e04def15b25d5c962dc\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f8db6475a83649689c087a8f52486fcc53e627e9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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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.
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