CVE-2026-98017

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

• https://git.kernel.org/stable/c/156a3bab69744e9225bb9eff8c5cc53da18d5a2e 416baaa9-dc9f-4396-8d5f-8c081fb06d67
• https://git.kernel.org/stable/c/20bf6fa34b345333971bd4464a322cce87b83f4e 416baaa9-dc9f-4396-8d5f-8c081fb06d67
• https://git.kernel.org/stable/c/5bfe927c5b4b290fad529186218c728589b4b101 416baaa9-dc9f-4396-8d5f-8c081fb06d67
• https://git.kernel.org/stable/c/e6662f2100f8d33b0f4d0047c219efd6bba186ea 416baaa9-dc9f-4396-8d5f-8c081fb06d67

The full cvelistV5 record. Download as CVE-2026-98017.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/net/sch_generic.h",
            "net/sched/sch_api.c",
            "net/sched/sch_generic.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "20bf6fa34b345333971bd4464a322cce87b83f4e",
              "status": "affected",
              "version": "51ab2994c387c80b45caf8b8067b3f3b97771d25",
              "versionType": "git"
            },
            {
              "lessThan": "156a3bab69744e9225bb9eff8c5cc53da18d5a2e",
              "status": "affected",
              "version": "51ab2994c387c80b45caf8b8067b3f3b97771d25",
              "versionType": "git"
            },
            {
              "lessThan": "5bfe927c5b4b290fad529186218c728589b4b101",
              "status": "affected",
              "version": "51ab2994c387c80b45caf8b8067b3f3b97771d25",
              "versionType": "git"
            },
            {
              "lessThan": "e6662f2100f8d33b0f4d0047c219efd6bba186ea",
              "status": "affected",
              "version": "51ab2994c387c80b45caf8b8067b3f3b97771d25",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/net/sch_generic.h",
            "net/sched/sch_api.c",
            "net/sched/sch_generic.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.16"
            },
            {
              "lessThan": "4.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "4.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "4.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.7",
                  "versionStartIncluding": "4.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc3",
                  "versionStartIncluding": "4.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: defer qdisc freeing after failed creation\n\nAn RTM_NEWQDISC request can make clsact bind a populated shared ingress\nblock during ->init(), publishing an embedded mini_Qdisc to lockless\nreaders.  If the same request has an invalid TCA_RATE, estimator setup\nfails after ->init(); the unwind removes the pointer but synchronously\nfrees its containing qdisc while tc_run() may still hold it.\n\nRetire failed qdiscs through the same RCU helper as normal destruction.\nInline the synchronous free into the callback now that no direct callers\nremain."
        }
      ],
      "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 trigger is a local rtnetlink RTM_NEWQDISC message (tc_modify_qdisc -> qdisc_create) with a clsact kind, a shared TCA_INGRESS_BLOCK and an invalid TCA_RATE. Packets only drive the reader side (tc_run), and no remote peer supplies the input that causes the bug.\nAC:L - The attacker controls both sides of the race: they repeat the failing clsact create, which runs qdisc_free() with no grace period, while pushing traffic through their own veth/dummy device so that tc_run() dereferences the published miniq. No outside condition is needed.\nPR:L - tc_modify_qdisc only needs CAP_NET_ADMIN in the netns that owns the device, which an unprivileged user gets through unshare -Urn plus a self-created veth/dummy interface. That makes it reachable as PR:L rather than requiring init-namespace root.\nUI:N - The attacker performs every step themselves: creating the shared block and filter, sending the failing RTM_NEWQDISC, and generating traffic. No victim action is needed.\nS:U - The use-after-free and any resulting privilege escalation stay inside the same kernel security authority. No hypervisor or IOMMU boundary is crossed.\nC:H - The mini_Qdisc embedded in the freed qdisc (a kmalloc'd object, so its slot can be reclaimed) is read by tc_run: miniq->block and miniq->filter_list are passed to tcf_classify. With a sprayed replacement object, the attacker controls these pointers, which can be used to leak kernel memory.\nI:H - tc_run calls mini_qdisc_bstats_cpu_update(), which writes through the cpu_bstats pointer taken from the freed object, and tcf_classify follows a filter_list the attacker can control. After reclaim, this gives a controlled write and a path to hijacking control flow.\nA:H - Freeing the qdisc while RCU readers in tc_run still hold its embedded miniq leads to KASAN splats and oopses when the packet path touches the freed or reallocated memory. The result is a kernel crash."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T14:41:50.690Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/20bf6fa34b345333971bd4464a322cce87b83f4e"
        },
        {
          "url": "https://git.kernel.org/stable/c/156a3bab69744e9225bb9eff8c5cc53da18d5a2e"
        },
        {
          "url": "https://git.kernel.org/stable/c/5bfe927c5b4b290fad529186218c728589b4b101"
        },
        {
          "url": "https://git.kernel.org/stable/c/e6662f2100f8d33b0f4d0047c219efd6bba186ea"
        }
      ],
      "title": "net/sched: defer qdisc freeing after failed creation",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98017",
    "datePublished": "2026-09-25T10:23:39.107Z",
    "dateReserved": "2026-09-25T10:19:56.069Z",
    "dateUpdated": "2026-09-25T14:41:50.690Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}