CVE-2026-92489 (GCVE-0-2026-92489)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:10 – Updated: 2026-09-18 17:55
VLAI
Title
xfrm: Fix skb double-free in xfrm_dev_direct_output()
Summary
In the Linux kernel, the following vulnerability has been resolved: xfrm: Fix skb double-free in xfrm_dev_direct_output() A return value other than 1 from local_out() means that the skb has been consumed or its ownership was transferred. xfrm_dev_direct_output() nevertheless frees the skb on this path, causing a double-free when netfilter drops the packet and invalidating any other owner. Return the local_out() result directly, matching the ownership handling in xfrm_output_resume().
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: bfb9b9404a53a72524ce695551755117e9d3deb0 , < 621871b696b108026bf4b44ed4085ffa2102f417 (git)
Affected: a0395e96831adee8ffa016bf958e4dce9ece656e , < bc9297796bfdcc8d9609236e54519a4f38737aac (git)
Affected: 5eddd76ec2fd1988f0a3450fde9730b10dd22992 , < 02deb637e965950148752a304dd1471212dd6470 (git)
Affected: 5eddd76ec2fd1988f0a3450fde9730b10dd22992 , < 56a347950e661c1a7f8f31c43a2ea53c2323b6f4 (git)
Affected: 5eddd76ec2fd1988f0a3450fde9730b10dd22992 , < 2aed51fc58d9ce450e2c116efb956160fd06fa02 (git)
Affected: d1d673a5bede3767252cff19c0ab1e5387c6f43f (git)
Affected: 6.6.85 , < 6.6.157 (semver)
Affected: 6.12.21 , < 6.12.110 (semver)
Affected: 6.13.9 , < 6.14 (semver)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.6.157 , ≤ 6.6.* (semver)
Unaffected: 6.12.110 , ≤ 6.12.* (semver)
Unaffected: 6.18.52 , ≤ 6.18.* (semver)
Unaffected: 7.2.6 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
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              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
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          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "6.6.85",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "6.12.21",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
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                {
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                  "versionStartIncluding": "6.13.9",
                  "vulnerable": true
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: Fix skb double-free in xfrm_dev_direct_output()\n\nA return value other than 1 from local_out() means that the skb has been\nconsumed or its ownership was transferred. xfrm_dev_direct_output()\nnevertheless frees the skb on this path, causing a double-free when\nnetfilter drops the packet and invalidating any other owner.\n\nReturn the local_out() result directly, matching the ownership handling\nin xfrm_output_resume()."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "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"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - A received IPv4/IPv6 packet that ip_forward()/ip6_forward() passes through xfrm4_route_forward()/xfrm6_route_forward() reaches xfrm4_output()/xfrm6_output() then xfrm_output(); for an XFRM_DEV_OFFLOAD_PACKET tunnel SA with skb-\u003esk NULL, that forwarded inner IP packet is what xfrm_dev_direct_output() processes.\nAC:L - xfrm_dev_direct_output() calls nf_reset_ct() then dst-\u003eops-\u003elocal_out (__ip_local_out/__ip6_local_out), so NF_INET_LOCAL_OUT consumes the skb on DROP/QUEUE/STOLEN. The attacker owns the forwarded packet and can force that verdict (iptables/nft DROP, or nf_conntrack_in() NF_DROP when resolve_normal_ct() fails after flooding new 5-tuples); no race is required.\nPR:N - ip_forward() and ip6_forward() take the skb with no socket or credentials; XFRM matching is only the received packet\u0027s IP selectors, not an authenticated session. CAP_NET_ADMIN is needed on the victim to install the packet-offload SA, not for the attacker who sends the inner packet.\nUI:N - The attacker triggers the bug only by sending IP packets that an already-configured packet-offload tunnel gateway forwards into xfrm_dev_direct_output(); no victim mount, open, or confirmation is required at exploit time.\nS:U - The sk_buff double-free in xfrm_dev_direct_output() corrupts kernel heap in the same kernel that performs IPsec output and is not a KVM/Xen guest-to-host escape or an IOMMU/DMA boundary bypass.\nC:H - When local_out() returns != 1, nf_hook_slow() has already kfree_skb_reason()\u0027d the skb on NF_DROP (or another owner holds it); the extra kfree_skb() in xfrm_dev_direct_output() is a sk_buff slab double-free that can be reclaimed with crafted packets to read kernel memory.\nI:H - The same sk_buff double-free after __ip_local_out()/__ip6_local_out() transfers ownership lets the attacker reallocate the freed object and obtain a kernel write and control-flow hijack primitive, not a crash-only integrity effect.\nA:H - The extra kfree_skb() in xfrm_dev_direct_output() when local_out() has already consumed the skb corrupts the sk_buff cache and causes a kernel oops or panic."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-18T17:55:28.166Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/621871b696b108026bf4b44ed4085ffa2102f417"
        },
        {
          "url": "https://git.kernel.org/stable/c/bc9297796bfdcc8d9609236e54519a4f38737aac"
        },
        {
          "url": "https://git.kernel.org/stable/c/02deb637e965950148752a304dd1471212dd6470"
        },
        {
          "url": "https://git.kernel.org/stable/c/56a347950e661c1a7f8f31c43a2ea53c2323b6f4"
        },
        {
          "url": "https://git.kernel.org/stable/c/2aed51fc58d9ce450e2c116efb956160fd06fa02"
        }
      ],
      "title": "xfrm: Fix skb double-free in xfrm_dev_direct_output()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-92489",
    "datePublished": "2026-09-17T16:10:04.126Z",
    "dateReserved": "2026-09-16T12:21:13.871Z",
    "dateUpdated": "2026-09-18T17:55:28.166Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-92489",
      "date": "2026-09-27",
      "epss": "0.00671",
      "percentile": "0.50056"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-24T01:04:31.000Z",
      "cve": "CVE-2026-92489",
      "id": "msrc_CVE-2026-92489",
      "initial_release_date": "2026-09-19T01:01:44.000Z",
      "product_status:fixed": "1",
      "product_status:known_affected": "2",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "xfrm: Fix skb double-free in xfrm_dev_direct_output()",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-92489.json",
      "version": "4"
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                "versions": [
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: Fix skb double-free in xfrm_dev_direct_output()\n\nA return value other than 1 from local_out() means that the skb has been\nconsumed or its ownership was transferred. xfrm_dev_direct_output()\nnevertheless frees the skb on this path, causing a double-free when\nnetfilter drops the packet and invalidating any other owner.\n\nReturn the local_out() result directly, matching the ownership handling\nin xfrm_output_resume()."
          }
        ],
        "id": "CVE-2026-92489",
        "lastModified": "2026-09-18T18:18:13.037",
        "metrics": {
          "cvssMetricV31": [
            {
              "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"
            }
          ]
        },
        "published": "2026-09-17T17:17:51.007",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/02deb637e965950148752a304dd1471212dd6470"
          },
          {
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/bc9297796bfdcc8d9609236e54519a4f38737aac"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • 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.
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  • 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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