CVE-2026-90099 (GCVE-0-2026-90099)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:06 – Updated: 2026-10-21 12:49
VLAI
Title
net/sched: account classifier filter allocations to memcg
Summary
In the Linux kernel, the following vulnerability has been resolved: net/sched: account classifier filter allocations to memcg Allocations in the tc classifier *_change() paths (filter objects, per-CPU counters, and per-filter aux data) use plain GFP_KERNEL without __GFP_ACCOUNT, allowing unprivileged users to pin kernel memory outside memcg charging. The shared tcf_exts_init_ex() action array allocation in cls_api.c was also uncharged; this patch closes it along with the per-classifier filter-object/percpu/aux allocations that remain unaccounted. Add GFP_KERNEL_ACCOUNT to: - the shared tcf_exts_init_ex() action array (cls_api.c), common to every filter of every classifier (32 pointers, 256 bytes); - the filter-object, per-CPU-counter, and per-filter aux allocations in cls_basic, cls_bpf, cls_cgroup, cls_flow, cls_flower, cls_fw, cls_matchall, cls_route and cls_u32; - the u32_init_knode() replace-path knode allocation (cls_u32.c), which allocates the same struct tc_u_knode + sel.keys on every replace of an existing knode and was missed by the create-path-only conversion. Also fix the cls_basic error path: basic_change() inserts fnew into the IDR before allocating the per-CPU counter. If alloc_percpu() fails the errout path kfree'd fnew without idr_remove, leaving a dangling pointer in the IDR. With GFP_KERNEL_ACCOUNT the percpu alloc becomes failable on demand (memcg at memory.max), making the dead path attacker-reachable and burning the handle permanently. Add the idr_remove on the percpu failure path, matching the basic_set_parms failure-path pattern. Note: vega@nebusec.ai provided a poc for basic_cls, but it was easy to extend to the other classifiers. Conditions to recreate the bug: - CONFIG_NET_SCHED, CONFIG_NET_CLS_* (the classifier being used), CONFIG_NET_CLS_ACT, CONFIG_MEMCG, CONFIG_USER_NS, CONFIG_NET_NS. - Unprivileged user in a fresh user+network namespace (unshare -Urn), or root with CAP_NET_ADMIN. - Create a large number of tc filters (e.g. tc filter add dev lo ingress ... <classifier> ...) while watching a memcg-limited cgroup: system slab grows far faster than memory.current, pinning kernel memory outside memcg charging.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7056 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0da974f4f303a6842516b764507e3c0a03f41e5a , < 5fbb06d4f3d4c509ffe95572384a498bf319e5bf (git)
Affected: 0da974f4f303a6842516b764507e3c0a03f41e5a , < bf6006cea193cf065f7a64fc7974247f8112af33 (git)
Affected: 0da974f4f303a6842516b764507e3c0a03f41e5a , < 68fb30607169c92de57c5c82b6af8a733af1cc09 (git)
Affected: 0da974f4f303a6842516b764507e3c0a03f41e5a , < 18c68c8f3d3ff0a4def1391021b439c4333a6c71 (git)
Affected: 0da974f4f303a6842516b764507e3c0a03f41e5a , < 1beb81947eb486716af80db7a584f9e9fef7e003 (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.18
Unaffected: 0 , < 2.6.18 (semver)
Unaffected: 6.6.160 , ≤ 6.6.* (semver)
Unaffected: 6.12.114 , ≤ 6.12.* (semver)
Unaffected: 6.18.57 , ≤ 6.18.* (semver)
Unaffected: 7.2.6 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/cls_api.c",
            "net/sched/cls_basic.c",
            "net/sched/cls_bpf.c",
            "net/sched/cls_cgroup.c",
            "net/sched/cls_flow.c",
            "net/sched/cls_flower.c",
            "net/sched/cls_fw.c",
            "net/sched/cls_matchall.c",
            "net/sched/cls_route.c",
            "net/sched/cls_u32.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5fbb06d4f3d4c509ffe95572384a498bf319e5bf",
              "status": "affected",
              "version": "0da974f4f303a6842516b764507e3c0a03f41e5a",
              "versionType": "git"
            },
            {
              "lessThan": "bf6006cea193cf065f7a64fc7974247f8112af33",
              "status": "affected",
              "version": "0da974f4f303a6842516b764507e3c0a03f41e5a",
              "versionType": "git"
            },
            {
              "lessThan": "68fb30607169c92de57c5c82b6af8a733af1cc09",
              "status": "affected",
              "version": "0da974f4f303a6842516b764507e3c0a03f41e5a",
              "versionType": "git"
            },
            {
              "lessThan": "18c68c8f3d3ff0a4def1391021b439c4333a6c71",
              "status": "affected",
              "version": "0da974f4f303a6842516b764507e3c0a03f41e5a",
              "versionType": "git"
            },
            {
              "lessThan": "1beb81947eb486716af80db7a584f9e9fef7e003",
              "status": "affected",
              "version": "0da974f4f303a6842516b764507e3c0a03f41e5a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/sched/cls_api.c",
            "net/sched/cls_basic.c",
            "net/sched/cls_bpf.c",
            "net/sched/cls_cgroup.c",
            "net/sched/cls_flow.c",
            "net/sched/cls_flower.c",
            "net/sched/cls_fw.c",
            "net/sched/cls_matchall.c",
            "net/sched/cls_route.c",
            "net/sched/cls_u32.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.18"
            },
            {
              "lessThan": "2.6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.114",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.57",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.160",
                  "versionStartIncluding": "2.6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.114",
                  "versionStartIncluding": "2.6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.57",
                  "versionStartIncluding": "2.6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "2.6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "2.6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: account classifier filter allocations to memcg\n\nAllocations in the tc classifier *_change() paths (filter objects,\nper-CPU counters, and per-filter aux data) use plain GFP_KERNEL without\n__GFP_ACCOUNT, allowing unprivileged users to pin kernel memory outside\nmemcg charging. The shared tcf_exts_init_ex() action array allocation in\ncls_api.c was also uncharged; this patch closes it along with the\nper-classifier filter-object/percpu/aux allocations that remain\nunaccounted.\n\nAdd GFP_KERNEL_ACCOUNT to:\n- the shared tcf_exts_init_ex() action array (cls_api.c), common to every\n  filter of every classifier (32 pointers, 256 bytes);\n- the filter-object, per-CPU-counter, and per-filter aux allocations in\n  cls_basic, cls_bpf, cls_cgroup, cls_flow, cls_flower, cls_fw,\n  cls_matchall, cls_route and cls_u32;\n- the u32_init_knode() replace-path knode allocation (cls_u32.c), which\n  allocates the same struct tc_u_knode + sel.keys on every replace of an\n  existing knode and was missed by the create-path-only conversion.\n\nAlso fix the cls_basic error path: basic_change() inserts fnew into the\nIDR before allocating the per-CPU counter. If alloc_percpu() fails the\nerrout path kfree\u0027d fnew without idr_remove, leaving a dangling pointer\nin the IDR. With GFP_KERNEL_ACCOUNT the percpu alloc becomes failable\non demand (memcg at memory.max), making the dead path attacker-reachable\nand burning the handle permanently. Add the idr_remove on the percpu\nfailure path, matching the basic_set_parms failure-path pattern.\n\nNote: vega@nebusec.ai provided a poc for basic_cls, but it was easy to\nextend to the other classifiers.\n\nConditions to recreate the bug:\n- CONFIG_NET_SCHED, CONFIG_NET_CLS_* (the classifier being used),\n  CONFIG_NET_CLS_ACT, CONFIG_MEMCG, CONFIG_USER_NS, CONFIG_NET_NS.\n- Unprivileged user in a fresh user+network namespace (unshare -Urn),\n  or root with CAP_NET_ADMIN.\n- Create a large number of tc filters (e.g. tc filter add dev lo\n  ingress ... \u003cclassifier\u003e ...) while watching a memcg-limited cgroup:\n  system slab grows far faster than memory.current, pinning kernel\n  memory outside memcg charging."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:49:50.191Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/5fbb06d4f3d4c509ffe95572384a498bf319e5bf"
        },
        {
          "url": "https://git.kernel.org/stable/c/bf6006cea193cf065f7a64fc7974247f8112af33"
        },
        {
          "url": "https://git.kernel.org/stable/c/68fb30607169c92de57c5c82b6af8a733af1cc09"
        },
        {
          "url": "https://git.kernel.org/stable/c/18c68c8f3d3ff0a4def1391021b439c4333a6c71"
        },
        {
          "url": "https://git.kernel.org/stable/c/1beb81947eb486716af80db7a584f9e9fef7e003"
        }
      ],
      "title": "net/sched: account classifier filter allocations to memcg",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90099",
    "datePublished": "2026-09-17T16:06:10.858Z",
    "dateReserved": "2026-09-11T19:38:34.786Z",
    "dateUpdated": "2026-10-21T12:49:50.191Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-90099",
      "date": "2026-10-25",
      "epss": "0.00209",
      "percentile": "0.10942"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/sched/cls_api.c",
                  "net/sched/cls_basic.c",
                  "net/sched/cls_bpf.c",
                  "net/sched/cls_cgroup.c",
                  "net/sched/cls_flow.c",
                  "net/sched/cls_flower.c",
                  "net/sched/cls_fw.c",
                  "net/sched/cls_matchall.c",
                  "net/sched/cls_route.c",
                  "net/sched/cls_u32.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "5fbb06d4f3d4c509ffe95572384a498bf319e5bf",
                    "status": "affected",
                    "version": "0da974f4f303a6842516b764507e3c0a03f41e5a",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "bf6006cea193cf065f7a64fc7974247f8112af33",
                    "status": "affected",
                    "version": "0da974f4f303a6842516b764507e3c0a03f41e5a",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "68fb30607169c92de57c5c82b6af8a733af1cc09",
                    "status": "affected",
                    "version": "0da974f4f303a6842516b764507e3c0a03f41e5a",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "18c68c8f3d3ff0a4def1391021b439c4333a6c71",
                    "status": "affected",
                    "version": "0da974f4f303a6842516b764507e3c0a03f41e5a",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "1beb81947eb486716af80db7a584f9e9fef7e003",
                    "status": "affected",
                    "version": "0da974f4f303a6842516b764507e3c0a03f41e5a",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "net/sched/cls_api.c",
                  "net/sched/cls_basic.c",
                  "net/sched/cls_bpf.c",
                  "net/sched/cls_cgroup.c",
                  "net/sched/cls_flow.c",
                  "net/sched/cls_flower.c",
                  "net/sched/cls_fw.c",
                  "net/sched/cls_matchall.c",
                  "net/sched/cls_route.c",
                  "net/sched/cls_u32.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "2.6.18"
                  },
                  {
                    "lessThan": "2.6.18",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.160",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.114",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.57",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.2.*",
                    "status": "unaffected",
                    "version": "7.2.6",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "7.3",
                    "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\nnet/sched: account classifier filter allocations to memcg\n\nAllocations in the tc classifier *_change() paths (filter objects,\nper-CPU counters, and per-filter aux data) use plain GFP_KERNEL without\n__GFP_ACCOUNT, allowing unprivileged users to pin kernel memory outside\nmemcg charging. The shared tcf_exts_init_ex() action array allocation in\ncls_api.c was also uncharged; this patch closes it along with the\nper-classifier filter-object/percpu/aux allocations that remain\nunaccounted.\n\nAdd GFP_KERNEL_ACCOUNT to:\n- the shared tcf_exts_init_ex() action array (cls_api.c), common to every\n  filter of every classifier (32 pointers, 256 bytes);\n- the filter-object, per-CPU-counter, and per-filter aux allocations in\n  cls_basic, cls_bpf, cls_cgroup, cls_flow, cls_flower, cls_fw,\n  cls_matchall, cls_route and cls_u32;\n- the u32_init_knode() replace-path knode allocation (cls_u32.c), which\n  allocates the same struct tc_u_knode + sel.keys on every replace of an\n  existing knode and was missed by the create-path-only conversion.\n\nAlso fix the cls_basic error path: basic_change() inserts fnew into the\nIDR before allocating the per-CPU counter. If alloc_percpu() fails the\nerrout path kfree\u0027d fnew without idr_remove, leaving a dangling pointer\nin the IDR. With GFP_KERNEL_ACCOUNT the percpu alloc becomes failable\non demand (memcg at memory.max), making the dead path attacker-reachable\nand burning the handle permanently. Add the idr_remove on the percpu\nfailure path, matching the basic_set_parms failure-path pattern.\n\nNote: vega@nebusec.ai provided a poc for basic_cls, but it was easy to\nextend to the other classifiers.\n\nConditions to recreate the bug:\n- CONFIG_NET_SCHED, CONFIG_NET_CLS_* (the classifier being used),\n  CONFIG_NET_CLS_ACT, CONFIG_MEMCG, CONFIG_USER_NS, CONFIG_NET_NS.\n- Unprivileged user in a fresh user+network namespace (unshare -Urn),\n  or root with CAP_NET_ADMIN.\n- Create a large number of tc filters (e.g. tc filter add dev lo\n  ingress ... \u003cclassifier\u003e ...) while watching a memcg-limited cgroup:\n  system slab grows far faster than memory.current, pinning kernel\n  memory outside memcg charging."
          }
        ],
        "id": "CVE-2026-90099",
        "lastModified": "2026-10-21T13:20:36.997",
        "metrics": {},
        "published": "2026-09-17T17:17:01.567",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/18c68c8f3d3ff0a4def1391021b439c4333a6c71"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/1beb81947eb486716af80db7a584f9e9fef7e003"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/5fbb06d4f3d4c509ffe95572384a498bf319e5bf"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/68fb30607169c92de57c5c82b6af8a733af1cc09"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/bf6006cea193cf065f7a64fc7974247f8112af33"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-10-13T13:22:46+00:00",
      "cve": "CVE-2026-90099",
      "id": "CVE-2026-90099",
      "initial_release_date": "2026-09-17T00:00:00+00:00",
      "product_status:known_affected": "277",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net/sched: account classifier filter allocations to memcg",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90099.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "low",
      "current_release_date": "2026-10-20T00:47:43Z",
      "cve": "CVE-2026-90099",
      "id": "CVE-2026-90099",
      "initial_release_date": "2026-09-18T00:21:32Z",
      "product_status:known_affected": "348",
      "product_status:recommended": "4",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-90099",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-90099.json",
      "version": "7"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

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.

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.