Vulnerability-Lookup

CVE-2026-74715 (GCVE-0-2026-74715)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:33 – Updated: 2026-08-25 05:41

Title

bpf: Fix netns reference imbalance in conntrack kfuncs

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix netns reference imbalance in conntrack kfuncs The opts argument of the BPF conntrack kfuncs can point to a shared map value. __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read opts->netns_id separately when acquiring and releasing the network namespace reference. The reference imbalance can occur as follows: CPU 0 CPU 1 read opts->netns_id (-1) skip get_net_ns_by_id() write opts->netns_id (id) read opts->netns_id (id) put_net(net) /* no matching get */ The reverse transition leaks the reference. Repeating the unmatched put can destroy a live namespace and crash later users. The kernel reported: Oops: general protection fault, probably for non-canonical address KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef] RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700 Call Trace: __sys_bpf+0x1662/0x50c0 __x64_sys_bpf+0x73/0xb0 do_syscall_64+0xf9/0x540 entry_SYSCALL_64_after_hwframe+0x77/0x7f Kernel panic - not syncing: Fatal exception Snapshot every input field of opts with READ_ONCE() before validating or using it. The netns_id snapshot keeps the namespace get/put pair balanced, while the other snapshots keep the remaining options from changing partway through an invocation. The individual reads can still observe an inconsistent combination during a concurrent update, but each selected field value remains stable for that invocation.

Severity

7.8 (High)


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

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/e5e060eb63d10b41a…
https://git.kernel.org/stable/c/fdeba03fea78407a8…

Impacted products

2 products

Vendor	Product	Version	CPE status
Linux	Linux	Affected: aed8ee7feb44b6537af1e0b4f03365d42928be38 , < e5e060eb63d10b41ab60fd955649479d99b38210 (git) Affected: aed8ee7feb44b6537af1e0b4f03365d42928be38 , < fdeba03fea78407a8c52faa99177c9f7f29f90eb (git)	guessed
Linux	Linux	Affected: 6.0 Unaffected: 0 , < 6.0 (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_conntrack_bpf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e5e060eb63d10b41ab60fd955649479d99b38210",
              "status": "affected",
              "version": "aed8ee7feb44b6537af1e0b4f03365d42928be38",
              "versionType": "git"
            },
            {
              "lessThan": "fdeba03fea78407a8c52faa99177c9f7f29f90eb",
              "status": "affected",
              "version": "aed8ee7feb44b6537af1e0b4f03365d42928be38",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_conntrack_bpf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "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": "7.1.9",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix netns reference imbalance in conntrack kfuncs\n\nThe opts argument of the BPF conntrack kfuncs can point to a shared\nmap value.  __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read\nopts-\u003enetns_id separately when acquiring and releasing the network\nnamespace reference.\n\nThe reference imbalance can occur as follows:\n\n  CPU 0                                  CPU 1\n  read opts-\u003enetns_id (-1)\n  skip get_net_ns_by_id()\n                                         write opts-\u003enetns_id (id)\n  read opts-\u003enetns_id (id)\n  put_net(net) /* no matching get */\n\nThe reverse transition leaks the reference.  Repeating the unmatched put\ncan destroy a live namespace and crash later users.\n\nThe kernel reported:\n\n  Oops: general protection fault, probably for non-canonical address\n  KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]\n  RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700\n  Call Trace:\n   __sys_bpf+0x1662/0x50c0\n   __x64_sys_bpf+0x73/0xb0\n   do_syscall_64+0xf9/0x540\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n  Kernel panic - not syncing: Fatal exception\n\nSnapshot every input field of opts with READ_ONCE() before validating or\nusing it.  The netns_id snapshot keeps the namespace get/put pair\nbalanced, while the other snapshots keep the remaining options from\nchanging partway through an invocation.  The individual reads can still\nobserve an inconsistent combination during a concurrent update, but each\nselected field value remains stable for that invocation."
        }
      ],
      "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 in BPF conntrack kfuncs reached only via the bpf() syscall (load, BPF_PROG_TEST_RUN, or attached XDP/TC programs), not from remote packet handling alone; kernel guidance classifies BPF as Local.\nAC:L - Exploitation needs a race on opts-\u003enetns_id in a shared BPF map value, but the attacker authors the program, drives concurrent bpf_map_update_elem and kfunc calls, and can pin threads to different CPUs to win the race reliably.\nPR:L - Triggering bpf_xdp_ct_lookup/bpf_skb_ct_lookup requires loading XDP or TC-BPF programs, which needs CAP_BPF and CAP_NET_ADMIN; both are obtainable by an unprivileged user inside a user/network namespace via unshare.\nUI:N - No victim interaction is required; the attacker loads their own BPF program, supplies map-backed opts, and runs concurrent test-run or traffic to trigger the refcount imbalance themselves.\nS:U - Impact is premature destruction of a live network namespace and kernel crashes within the same kernel security domain; it does not cross a VM, container-to-host, or IOMMU boundary.\nC:H - Repeated unmatched put_net() can drop a live namespace refcount to zero and free it while still in use, creating a net-namespace use-after-free that can expose freed kernel memory and enable information disclosure.\nI:H - The refcount corruption can destroy active network namespaces and corrupt kernel networking state; such lifetime bugs are memory corruption primitives that can be leveraged for arbitrary kernel modification or control-flow hijacking.\nA:H - The fix commit documents a reproduced general protection fault and kernel panic in bpf_prog_test_run_xdp from a null-ptr-deref after the namespace is destroyed, confirming complete system availability loss."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-25T05:41:58.565Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e5e060eb63d10b41ab60fd955649479d99b38210"
        },
        {
          "url": "https://git.kernel.org/stable/c/fdeba03fea78407a8c52faa99177c9f7f29f90eb"
        }
      ],
      "title": "bpf: Fix netns reference imbalance in conntrack kfuncs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74715",
    "datePublished": "2026-08-22T15:33:10.262Z",
    "dateReserved": "2026-08-15T05:44:03.928Z",
    "dateUpdated": "2026-08-25T05:41:58.565Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74715",
      "date": "2026-08-25",
      "epss": "0.0012",
      "percentile": "0.0206"
    },
    "microsoft_vex": {
      "current_release_date": "2026-08-24T14:45:47.000Z",
      "cve": "CVE-2026-74715",
      "id": "msrc_CVE-2026-74715",
      "initial_release_date": "2026-08-24T01:12:14.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "bpf: Fix netns reference imbalance in conntrack kfuncs",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74715.json",
      "version": "2"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-74715\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-22T16:16:46.313\",\"lastModified\":\"2026-08-25T06:18:57.063\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbpf: Fix netns reference imbalance in conntrack kfuncs\\n\\nThe opts argument of the BPF conntrack kfuncs can point to a shared\\nmap value.  __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read\\nopts-\u003enetns_id separately when acquiring and releasing the network\\nnamespace reference.\\n\\nThe reference imbalance can occur as follows:\\n\\n  CPU 0                                  CPU 1\\n  read opts-\u003enetns_id (-1)\\n  skip get_net_ns_by_id()\\n                                         write opts-\u003enetns_id (id)\\n  read opts-\u003enetns_id (id)\\n  put_net(net) /* no matching get */\\n\\nThe reverse transition leaks the reference.  Repeating the unmatched put\\ncan destroy a live namespace and crash later users.\\n\\nThe kernel reported:\\n\\n  Oops: general protection fault, probably for non-canonical address\\n  KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]\\n  RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700\\n  Call Trace:\\n   __sys_bpf+0x1662/0x50c0\\n   __x64_sys_bpf+0x73/0xb0\\n   do_syscall_64+0xf9/0x540\\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\\n  Kernel panic - not syncing: Fatal exception\\n\\nSnapshot every input field of opts with READ_ONCE() before validating or\\nusing it.  The netns_id snapshot keeps the namespace get/put pair\\nbalanced, while the other snapshots keep the remaining options from\\nchanging partway through an invocation.  The individual reads can still\\nobserve an inconsistent combination during a concurrent update, but each\\nselected field value remains stable for that invocation.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/netfilter/nf_conntrack_bpf.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"aed8ee7feb44b6537af1e0b4f03365d42928be38\",\"lessThan\":\"e5e060eb63d10b41ab60fd955649479d99b38210\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"aed8ee7feb44b6537af1e0b4f03365d42928be38\",\"lessThan\":\"fdeba03fea78407a8c52faa99177c9f7f29f90eb\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/netfilter/nf_conntrack_bpf.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.0\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.0\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.9\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/e5e060eb63d10b41ab60fd955649479d99b38210\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fdeba03fea78407a8c52faa99177c9f7f29f90eb\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-25T08:55:49+00:00",
      "cve": "CVE-2026-74715",
      "id": "CVE-2026-74715",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_affected": "108",
      "product_status:known_not_affected": "166",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: bpf: Fix netns reference imbalance in conntrack kfuncs",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74715.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-08-23T00:04:06Z",
      "cve": "CVE-2026-74715",
      "id": "CVE-2026-74715",
      "initial_release_date": "2026-08-23T00:04:06Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74715",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74715.json",
      "version": "2"
    }
  }
}

FKIE_CVE-2026-74715

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

Severity

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

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/e5e060eb63d10b41ab60fd955649479d99b38210
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/fdeba03fea78407a8c52faa99177c9f7f29f90eb

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_conntrack_bpf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e5e060eb63d10b41ab60fd955649479d99b38210",
              "status": "affected",
              "version": "aed8ee7feb44b6537af1e0b4f03365d42928be38",
              "versionType": "git"
            },
            {
              "lessThan": "fdeba03fea78407a8c52faa99177c9f7f29f90eb",
              "status": "affected",
              "version": "aed8ee7feb44b6537af1e0b4f03365d42928be38",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_conntrack_bpf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "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\nbpf: Fix netns reference imbalance in conntrack kfuncs\n\nThe opts argument of the BPF conntrack kfuncs can point to a shared\nmap value.  __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read\nopts-\u003enetns_id separately when acquiring and releasing the network\nnamespace reference.\n\nThe reference imbalance can occur as follows:\n\n  CPU 0                                  CPU 1\n  read opts-\u003enetns_id (-1)\n  skip get_net_ns_by_id()\n                                         write opts-\u003enetns_id (id)\n  read opts-\u003enetns_id (id)\n  put_net(net) /* no matching get */\n\nThe reverse transition leaks the reference.  Repeating the unmatched put\ncan destroy a live namespace and crash later users.\n\nThe kernel reported:\n\n  Oops: general protection fault, probably for non-canonical address\n  KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]\n  RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700\n  Call Trace:\n   __sys_bpf+0x1662/0x50c0\n   __x64_sys_bpf+0x73/0xb0\n   do_syscall_64+0xf9/0x540\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n  Kernel panic - not syncing: Fatal exception\n\nSnapshot every input field of opts with READ_ONCE() before validating or\nusing it.  The netns_id snapshot keeps the namespace get/put pair\nbalanced, while the other snapshots keep the remaining options from\nchanging partway through an invocation.  The individual reads can still\nobserve an inconsistent combination during a concurrent update, but each\nselected field value remains stable for that invocation."
    }
  ],
  "id": "CVE-2026-74715",
  "lastModified": "2026-08-25T06:18:57.063",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-22T16:16:46.313",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e5e060eb63d10b41ab60fd955649479d99b38210"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fdeba03fea78407a8c52faa99177c9f7f29f90eb"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

GHSA-8QQV-VCF6-Q7HX

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-25 06:31

Details

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix netns reference imbalance in conntrack kfuncs

The opts argument of the BPF conntrack kfuncs can point to a shared map value. __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read opts->netns_id separately when acquiring and releasing the network namespace reference.

The reference imbalance can occur as follows:

CPU 0 CPU 1 read opts->netns_id (-1) skip get_net_ns_by_id() write opts->netns_id (id) read opts->netns_id (id) put_net(net) / no matching get /

The reverse transition leaks the reference. Repeating the unmatched put can destroy a live namespace and crash later users.

The kernel reported:

Oops: general protection fault, probably for non-canonical address KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef] RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700 Call Trace: __sys_bpf+0x1662/0x50c0 __x64_sys_bpf+0x73/0xb0 do_syscall_64+0xf9/0x540 entry_SYSCALL_64_after_hwframe+0x77/0x7f Kernel panic - not syncing: Fatal exception

Snapshot every input field of opts with READ_ONCE() before validating or using it. The netns_id snapshot keeps the namespace get/put pair balanced, while the other snapshots keep the remaining options from changing partway through an invocation. The individual reads can still observe an inconsistent combination during a concurrent update, but each selected field value remains stable for that invocation.

Severity

7.8 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-74715"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:46Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix netns reference imbalance in conntrack kfuncs\n\nThe opts argument of the BPF conntrack kfuncs can point to a shared\nmap value.  __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read\nopts-\u003enetns_id separately when acquiring and releasing the network\nnamespace reference.\n\nThe reference imbalance can occur as follows:\n\n  CPU 0                                  CPU 1\n  read opts-\u003enetns_id (-1)\n  skip get_net_ns_by_id()\n                                         write opts-\u003enetns_id (id)\n  read opts-\u003enetns_id (id)\n  put_net(net) /* no matching get */\n\nThe reverse transition leaks the reference.  Repeating the unmatched put\ncan destroy a live namespace and crash later users.\n\nThe kernel reported:\n\n  Oops: general protection fault, probably for non-canonical address\n  KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]\n  RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700\n  Call Trace:\n   __sys_bpf+0x1662/0x50c0\n   __x64_sys_bpf+0x73/0xb0\n   do_syscall_64+0xf9/0x540\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n  Kernel panic - not syncing: Fatal exception\n\nSnapshot every input field of opts with READ_ONCE() before validating or\nusing it.  The netns_id snapshot keeps the namespace get/put pair\nbalanced, while the other snapshots keep the remaining options from\nchanging partway through an invocation.  The individual reads can still\nobserve an inconsistent combination during a concurrent update, but each\nselected field value remains stable for that invocation.",
  "id": "GHSA-8qqv-vcf6-q7hx",
  "modified": "2026-08-25T06:31:29Z",
  "published": "2026-08-22T18:30:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74715"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e5e060eb63d10b41ab60fd955649479d99b38210"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fdeba03fea78407a8c52faa99177c9f7f29f90eb"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

MSRC_CVE-2026-74715

Vulnerability from csaf_microsoft - Published: 2026-08-24 01:12 - Updated: 2026-08-24 14:45

Summary

bpf: Fix netns reference imbalance in conntrack kfuncs

Notes

Additional Resources: To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

Disclaimer: The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

CVE-2026-74715

Affected products

Known affected 1 product

Product	Identifier	Version	Remediation
Unresolved product id: 17084-1		—	None Available

References

4 references

URL	Category
https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self
https://support.microsoft.com/lifecycle	external
https://www.first.org/cvss	external
https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self

JSON

To clipboard

{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-74715 bpf: Fix netns reference imbalance in conntrack kfuncs - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74715.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "bpf: Fix netns reference imbalance in conntrack kfuncs",
    "tracking": {
      "current_release_date": "2026-08-24T14:45:47.000Z",
      "generator": {
        "date": "2026-08-25T07:02:58.282Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-74715",
      "initial_release_date": "2026-08-24T01:12:14.000Z",
      "revision_history": [
        {
          "date": "2026-08-24T01:12:14.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2026-08-24T14:45:47.000Z",
          "legacy_version": "2",
          "number": "2",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "3.0",
                "product": {
                  "name": "Azure Linux 3.0",
                  "product_id": "17084"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "azl3 kernel 0:6.6.150.1-1.azl3",
                "product": {
                  "name": "azl3 kernel 0:6.6.150.1-1.azl3",
                  "product_id": "1"
                }
              }
            ],
            "category": "product_name",
            "name": "kernel"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 kernel 0:6.6.150.1-1.azl3 as a component of Azure Linux 3.0",
          "product_id": "17084-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17084"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-74715",
      "notes": [
        {
          "category": "general",
          "text": "Linux",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "known_affected": [
          "17084-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-74715 bpf: Fix netns reference imbalance in conntrack kfuncs - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74715.json"
        }
      ],
      "remediations": [
        {
          "category": "none_available",
          "date": "2026-08-24T01:12:14.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17084-1"
          ]
        }
      ],
      "title": "bpf: Fix netns reference imbalance in conntrack kfuncs"
    }
  ]
}

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.

Action not permitted

CVE-2026-74715 (GCVE-0-2026-74715)

FKIE_CVE-2026-74715

GHSA-8QQV-VCF6-Q7HX

MSRC_CVE-2026-74715

Tags

Sightings

Nomenclature