{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2"
            },
            {
              "fixed": "4f0f4b09a95ef602fbdae948326beadd9c20eab3"
            },
            {
              "fixed": "0bc5a6280a132a2170c6fa742436e01b635f02de"
            },
            {
              "fixed": "448c34421b38ec7c93a0060a885218ca319d382b"
            },
            {
              "fixed": "82fdbf49b9f7528c82bf608cfa9710e5f81a198c"
            },
            {
              "fixed": "6e78792d8ce1fa3561713860ee8086901dde4f99"
            },
            {
              "fixed": "1a5c26e586481bc82abc19ac92c3d9f10518f525"
            },
            {
              "fixed": "16d21a27df3f50b7251c9388fc5a7ab22703b469"
            },
            {
              "fixed": "8f735d64382dcf162f4276d6699d03ad2f859c0b"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.12"
            },
            {
              "fixed": "5.10.270"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.221"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.188"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.157"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.110"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.52"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90058.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: bound qdisc_pkt_len to prevent qdisc soft lockup\n\nqdisc_get_stab() accepts a user-supplied size table, and\n__qdisc_calculate_pkt_len() amplifies qdisc_pkt_len() through the\noverhead, the size-table data (u16), and size_log (up to\nSTAB_SIZE_LOG_MAX). A crafted stab can therefore set qdisc_pkt_len()\nto ~1 GiB for an ordinary skb. Per-flow deficit schedulers such as\nDRR and ETS replenish one quantum per loop iteration; with a tiny\nquantum (1) they spin billions of times under the qdisc lock,\nproducing a soft lockup / RCU stall as illustrated by vega@nebusec.ai.\n\nCap the final qdisc_pkt_len() to QDISC_PKT_LEN_MAX so the size-table\namplification cannot drive deficit schedulers into an unbounded loop.\nA legitimate size table (e.g. qfq's overhead 999999999, which is\nhandled by dropping) is still accepted.\n\nIntroduce cap QDISC_PKT_LEN_MAX (1 \u003c\u003c 20) = 1 MiB which is well above\nany legitimate single-skb wire length: the largest current skb-\u003elen\nis GSO_MAX_SIZE (524280), and an ATM-style size table (53/48 cell tax)\namplifies that to ~578 KB, both comfortably below 1 MiB. At the same\ntime, 1 MiB bounds the deficit refill loop to ~1M iterations per\npacket with quantum=1, which completes in a few milliseconds well\nunder the demonstrated softlockup threshold (~10^9 iterations).\n\nConditions to recreate the bug:\n- CONFIG_NET_SCHED=y, CONFIG_NET_SCH_DRR=y (or CONFIG_NET_SCH_ETS=y).\n- Attach a DRR (or ETS) root qdisc with a crafted TCA_STAB that\n  amplifies qdisc_pkt_len to ~1 GiB (e.g. size_log=15, data=[32768]).\n- Add a class with a tiny quantum of 1 and send one small packet; the\n  deficit loop spins billions of times under the qdisc lock and trips\n  the softlockup detector (panic with kernel.softlockup_panic=1).\n- Reachable as root or from an unprivileged user in a fresh user+net\n  namespace (unshare -Urn) with namespace-local CAP_NET_ADMIN.",
  "id": "CVE-2026-90058",
  "modified": "2026-09-19T03:30:51.802231061Z",
  "published": "2026-09-17T16:05:43.184Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0bc5a6280a132a2170c6fa742436e01b635f02de"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/16d21a27df3f50b7251c9388fc5a7ab22703b469"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1a5c26e586481bc82abc19ac92c3d9f10518f525"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/448c34421b38ec7c93a0060a885218ca319d382b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4f0f4b09a95ef602fbdae948326beadd9c20eab3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6e78792d8ce1fa3561713860ee8086901dde4f99"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/82fdbf49b9f7528c82bf608cfa9710e5f81a198c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8f735d64382dcf162f4276d6699d03ad2f859c0b"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90058.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90058"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "net/sched: bound qdisc_pkt_len to prevent qdisc soft lockup"
}