CVE-2026-72463 (GCVE-0-2026-72463)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:57 – Updated: 2026-08-17 05:44
VLAI
Title
xfrm: Fix dev use-after-free in xfrm async resumption
Summary
In the Linux kernel, the following vulnerability has been resolved: xfrm: Fix dev use-after-free in xfrm async resumption xfrm async resumption hold skb->dev refcnt until after transport_finish. However, xfrm_rcv_cb may modify skb->dev to tunnel dev without taking device reference, such as vti_rcv_cb. The subsequent async resumption will decrement the tunnel device's reference count, which lead to uaf of tunnel dev and refcnt leak of orig dev as below: unregister_netdevice: waiting for vti1 to become free. Usage count = -2 Stash the original skb->dev to fix refcnt imbalance. The new skb->dev set by xfrm_rcv_cb can race with device teardown. Extend rcu protection over xfrm_rcv_cb and transport_finish to prevent races.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1c428b03840094410c5fb6a5db30640486bbbfcb , < 63a30015199912bd5055bead8001b1ae68a67cdb (git)
Affected: 1c428b03840094410c5fb6a5db30640486bbbfcb , < 8045c0df98d4f14c54e5cb875f1c9c0ce89fe4ff (git)
Affected: 4236c30b437b80f673b9e08c8fae38b8d471ac9e (git)
Affected: 0f451b43c88bf2b9c038b414be580efee42e031b (git)
Affected: 5002beda5cac69d522dc54da0d5d463ed9c963d2 (git)
Affected: 6.12.94 , < 6.13 (semver)
Affected: 6.18.23 , < 6.19 (semver)
Affected: 6.19.13 , < 6.20 (semver)
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Linux Linux Affected: 7.0
Unaffected: 0 , < 7.0 (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
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          "product": "Linux",
          "programFiles": [
            "net/ipv4/xfrm4_input.c",
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              "versionType": "semver"
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            "net/ipv6/xfrm6_input.c",
            "net/xfrm/xfrm_input.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "version": "7.1.5",
              "versionType": "semver"
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              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "7.0",
                  "vulnerable": true
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: Fix dev use-after-free in xfrm async resumption\n\nxfrm async resumption hold skb-\u003edev refcnt until after transport_finish.\nHowever, xfrm_rcv_cb may modify skb-\u003edev to tunnel dev without taking\ndevice reference, such as vti_rcv_cb. The subsequent async resumption\nwill decrement the tunnel device\u0027s reference count, which lead to uaf\nof tunnel dev and refcnt leak of orig dev as below:\n\nunregister_netdevice: waiting for vti1 to become free. Usage count = -2\n\nStash the original skb-\u003edev to fix refcnt imbalance. The new skb-\u003edev set\nby xfrm_rcv_cb can race with device teardown. Extend rcu protection over\nxfrm_rcv_cb and transport_finish to prevent races."
        }
      ],
      "metrics": [
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            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
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              "lang": "en",
              "value": "AV:N - Reachable from the network receive path: remote ESP/AH (or UDP-encapsulated IPsec) packets hit ip_rcv \u2192 xfrm4/xfrm6 protocol handlers \u2192 vti/xfrmi input \u2192 xfrm_input() \u2192 async crypto resume, on Internet-facing IPsec/VTI/xfrmi VPN gateways and cloud endpoints.\nAC:L - Once async decryption resumes (encap_type=-1), vti_rcv_cb/xfrmi_rcv_cb retarget skb-\u003edev and the stale dev_put is deterministic; the attacker controls packet rate/volume to drive -EINPROGRESS and can race netdev teardown, so no uncontrollable victim-only conditions apply.\nPR:N - No local account, shell, or capability on the victim is required\u2014only network-delivered IPsec traffic accepted by a pre-configured VTI/xfrmi gateway (e.g., VPN peer, site-to-site endpoint); administrative IPsec setup is deployment state, not attacker privilege on the host.\nUI:N - Exploitation is fully automated by sending IPsec packets; no victim interaction such as mounting filesystems, opening files, or clicking links is needed.\nS:U - Impact is kernel net_device refcount corruption/UAF within the host kernel security authority; it does not cross VM, IOMMU, or sandbox boundaries (standard kernel privilege escalation, not escape).\nC:H - Use-after-free of a net_device after refcount underflow (e.g., usage count=-2) exposes freed netdev/slab memory; per kernel UAF guidance this provides a high-impact arbitrary-read primitive via heap grooming.\nI:H - Corrupting freed net_device structures and reference counts is classic heap UAF that can be shaped into arbitrary kernel writes and control-flow hijack for code execution, per kernel memory-corruption guidance.\nA:H - Refcount imbalance causes unregister_netdevice to hang (usage count=-2), kernel oops/panic during tunnel teardown, and reliable denial of service on IPsec gateways even before full exploitation."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:44:29.613Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/63a30015199912bd5055bead8001b1ae68a67cdb"
        },
        {
          "url": "https://git.kernel.org/stable/c/8045c0df98d4f14c54e5cb875f1c9c0ce89fe4ff"
        }
      ],
      "title": "xfrm: Fix dev use-after-free in xfrm async resumption",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72463",
    "datePublished": "2026-08-15T05:57:07.413Z",
    "dateReserved": "2026-08-09T03:40:39.933Z",
    "dateUpdated": "2026-08-17T05:44:29.613Z",
    "state": "PUBLISHED"
  },
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      "date": "2026-09-20",
      "epss": "0.0038",
      "percentile": "0.31846"
    },
    "nvd": {
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        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: Fix dev use-after-free in xfrm async resumption\n\nxfrm async resumption hold skb-\u003edev refcnt until after transport_finish.\nHowever, xfrm_rcv_cb may modify skb-\u003edev to tunnel dev without taking\ndevice reference, such as vti_rcv_cb. The subsequent async resumption\nwill decrement the tunnel device\u0027s reference count, which lead to uaf\nof tunnel dev and refcnt leak of orig dev as below:\n\nunregister_netdevice: waiting for vti1 to become free. Usage count = -2\n\nStash the original skb-\u003edev to fix refcnt imbalance. The new skb-\u003edev set\nby xfrm_rcv_cb can race with device teardown. Extend rcu protection over\nxfrm_rcv_cb and transport_finish to prevent races."
          }
        ],
        "id": "CVE-2026-72463",
        "lastModified": "2026-08-17T06:19:14.040",
        "metrics": {
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            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-08-15T06:22:20.303",
        "references": [
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          }
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-08-31T16:10:59+00:00",
      "cve": "CVE-2026-72463",
      "id": "CVE-2026-72463",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: xfrm: Fix dev use-after-free in xfrm async resumption",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72463.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-18T00:28:11Z",
      "cve": "CVE-2026-72463",
      "id": "CVE-2026-72463",
      "initial_release_date": "2026-08-27T16:52:27Z",
      "product_status:known_affected": "394",
      "product_status:known_not_affected": "325",
      "product_status:recommended": "107",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-72463",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72463.json",
      "version": "7"
    }
  }
}



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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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