Vulnerability-Lookup

FKIE_CVE-2026-74695

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-25 06:18

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_flow_table: drop existing skb dst before skb_dst_set_noref() Incoming skbs passing through netfilter flowtable offload hooks (or XFRM offload path) might already carry a ref-counted dst_entry assigned during earlier RX or routing steps. Calling skb_dst_set_noref() when skb already holds a ref-counted dst overwrites skb->_skb_refdst, leaking the previous dst_entry reference count and triggering a DEBUG_NET_WARN_ON_ONCE assertion in skb_dst_check_unset(): WARNING: at skb_dst_check_unset include/linux/skbuff.h:1170 WARNING: at skb_dst_set_noref include/linux/skbuff.h:1234 WARNING: at nf_flow_offload_ip_hook+0xf6c/0x2b60 net/netfilter/nf_flow_table_ip.c:864 Drop any existing dst_entry reference with skb_dst_drop(skb) before setting the non-referenced flowtable destination.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/12afa450a6a6c0cce2c42b7545a9958f62d8a00c
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/538e67e8c7889cf5f93951f5309d1bcb41f86036
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/8aecf0bbcc72605592134c917c222207d8f63ab0

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_flow_table_ip.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "12afa450a6a6c0cce2c42b7545a9958f62d8a00c",
              "status": "affected",
              "version": "2a79fd3908acd88e6cb0e620c314d7b1fee56a02",
              "versionType": "git"
            },
            {
              "lessThan": "538e67e8c7889cf5f93951f5309d1bcb41f86036",
              "status": "affected",
              "version": "2a79fd3908acd88e6cb0e620c314d7b1fee56a02",
              "versionType": "git"
            },
            {
              "lessThan": "8aecf0bbcc72605592134c917c222207d8f63ab0",
              "status": "affected",
              "version": "2a79fd3908acd88e6cb0e620c314d7b1fee56a02",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b4b1adf2e66ecc7125c4117e7aad9ff61e2cfd27",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "209dedf806d31095968f54323dbe62525b077b33",
              "versionType": "git"
            },
            {
              "lessThan": "4.17",
              "status": "affected",
              "version": "4.16.15",
              "versionType": "semver"
            },
            {
              "lessThan": "4.18",
              "status": "affected",
              "version": "4.17.1",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_flow_table_ip.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.18"
            },
            {
              "lessThan": "4.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_flow_table: drop existing skb dst before skb_dst_set_noref()\n\nIncoming skbs passing through netfilter flowtable offload hooks (or XFRM\noffload path) might already carry a ref-counted dst_entry assigned during\nearlier RX or routing steps.\n\nCalling skb_dst_set_noref() when skb already holds a ref-counted dst\noverwrites skb-\u003e_skb_refdst, leaking the previous dst_entry reference\ncount and triggering a DEBUG_NET_WARN_ON_ONCE assertion in\nskb_dst_check_unset():\n\n  WARNING: at skb_dst_check_unset include/linux/skbuff.h:1170\n  WARNING: at skb_dst_set_noref include/linux/skbuff.h:1234\n  WARNING: at nf_flow_offload_ip_hook+0xf6c/0x2b60 net/netfilter/nf_flow_table_ip.c:864\n\nDrop any existing dst_entry reference with skb_dst_drop(skb) before\nsetting the non-referenced flowtable destination."
    }
  ],
  "id": "CVE-2026-74695",
  "lastModified": "2026-08-25T06:18:53.000",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-22T16:16:44.050",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/12afa450a6a6c0cce2c42b7545a9958f62d8a00c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/538e67e8c7889cf5f93951f5309d1bcb41f86036"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8aecf0bbcc72605592134c917c222207d8f63ab0"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-74695 (GCVE-0-2026-74695)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:32 – Updated: 2026-08-25 05:41

Title

netfilter: nf_flow_table: drop existing skb dst before skb_dst_set_noref()

Summary

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/12afa450a6a6c0cce…
https://git.kernel.org/stable/c/538e67e8c7889cf5f…
https://git.kernel.org/stable/c/8aecf0bbcc7260559…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 2a79fd3908acd88e6cb0e620c314d7b1fee56a02 , < 12afa450a6a6c0cce2c42b7545a9958f62d8a00c (git) Affected: 2a79fd3908acd88e6cb0e620c314d7b1fee56a02 , < 538e67e8c7889cf5f93951f5309d1bcb41f86036 (git) Affected: 2a79fd3908acd88e6cb0e620c314d7b1fee56a02 , < 8aecf0bbcc72605592134c917c222207d8f63ab0 (git) Affected: b4b1adf2e66ecc7125c4117e7aad9ff61e2cfd27 (git) Affected: 209dedf806d31095968f54323dbe62525b077b33 (git) Affected: 4.16.15 , < 4.17 (semver) Affected: 4.17.1 , < 4.18 (semver)
Linux	Linux	Affected: 4.18 Unaffected: 0 , < 4.18 (semver) Unaffected: 6.18.45 , ≤ 6.18.* (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_flow_table_ip.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "12afa450a6a6c0cce2c42b7545a9958f62d8a00c",
              "status": "affected",
              "version": "2a79fd3908acd88e6cb0e620c314d7b1fee56a02",
              "versionType": "git"
            },
            {
              "lessThan": "538e67e8c7889cf5f93951f5309d1bcb41f86036",
              "status": "affected",
              "version": "2a79fd3908acd88e6cb0e620c314d7b1fee56a02",
              "versionType": "git"
            },
            {
              "lessThan": "8aecf0bbcc72605592134c917c222207d8f63ab0",
              "status": "affected",
              "version": "2a79fd3908acd88e6cb0e620c314d7b1fee56a02",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b4b1adf2e66ecc7125c4117e7aad9ff61e2cfd27",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "209dedf806d31095968f54323dbe62525b077b33",
              "versionType": "git"
            },
            {
              "lessThan": "4.17",
              "status": "affected",
              "version": "4.16.15",
              "versionType": "semver"
            },
            {
              "lessThan": "4.18",
              "status": "affected",
              "version": "4.17.1",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_flow_table_ip.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.18"
            },
            {
              "lessThan": "4.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.45",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.9",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.16.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.17.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_flow_table: drop existing skb dst before skb_dst_set_noref()\n\nIncoming skbs passing through netfilter flowtable offload hooks (or XFRM\noffload path) might already carry a ref-counted dst_entry assigned during\nearlier RX or routing steps.\n\nCalling skb_dst_set_noref() when skb already holds a ref-counted dst\noverwrites skb-\u003e_skb_refdst, leaking the previous dst_entry reference\ncount and triggering a DEBUG_NET_WARN_ON_ONCE assertion in\nskb_dst_check_unset():\n\n  WARNING: at skb_dst_check_unset include/linux/skbuff.h:1170\n  WARNING: at skb_dst_set_noref include/linux/skbuff.h:1234\n  WARNING: at nf_flow_offload_ip_hook+0xf6c/0x2b60 net/netfilter/nf_flow_table_ip.c:864\n\nDrop any existing dst_entry reference with skb_dst_drop(skb) before\nsetting the non-referenced flowtable destination."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The bug fires in nf_flow_offload_ip_hook on NF_NETDEV_INGRESS when remotely sourced IPv4/IPv6 packets matching an offloaded flow are received on nftables flowtable-bound interfaces, not via netlink configuration APIs.\nAC:L - Once a flowtable ingress hook and offloaded TCP/UDP flow exist, an attacker can reliably send matching traffic that reaches FLOW_OFFLOAD_XMIT_NEIGH or the XFRM offload path with a ref-counted skb dst; syzbot reproduced this without uncontrollable races.\nPR:N - Exploitation requires only sending network traffic through an already deployed nftables flow-offload path on an ingress device; no local account, authentication, or CAP_NET_ADMIN on the victim is needed to trigger the leak.\nUI:N - No victim interaction is required beyond normal network delivery; packets are processed automatically in softirq on the netdev ingress netfilter hook without opening files or mounting filesystems.\nS:U - Impact is confined to kernel refcount imbalance and availability degradation on the affected host; this is standard in-kernel compromise territory, not a VM escape, IOMMU bypass, or other cross-authority scope change.\nC:N - The flaw leaks a dst_entry reference by overwriting skb-\u003e_skb_refdst without releasing the prior dst; it does not expose kernel memory or provide an arbitrary read primitive.\nI:N - No unauthorized data modification occurs; the skb is forwarded using the intended flowtable destination while the previous dst reference is orphaned, not corrupted into a controllable write primitive.\nA:H - Each matching packet leaks a dst_entry refcount on the flowtable fast path, enabling sustained unauthenticated remote memory exhaustion on high-volume routers; CONFIG_DEBUG_NET builds also emit WARN_ON_ONCE during the overwrite."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-25T05:41:38.836Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/12afa450a6a6c0cce2c42b7545a9958f62d8a00c"
        },
        {
          "url": "https://git.kernel.org/stable/c/538e67e8c7889cf5f93951f5309d1bcb41f86036"
        },
        {
          "url": "https://git.kernel.org/stable/c/8aecf0bbcc72605592134c917c222207d8f63ab0"
        }
      ],
      "title": "netfilter: nf_flow_table: drop existing skb dst before skb_dst_set_noref()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74695",
    "datePublished": "2026-08-22T15:32:57.756Z",
    "dateReserved": "2026-08-15T05:44:03.926Z",
    "dateUpdated": "2026-08-25T05:41:38.836Z",
    "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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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FKIE_CVE-2026-74695

CVE-2026-74695 (GCVE-0-2026-74695)

Tags

Sightings

Nomenclature