{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "8b64678e0af8f4d62a40149baedebe78503a5255"
            },
            {
              "fixed": "a68e664ddf16ecae6d769d6a2eb356f8abab75c9"
            },
            {
              "fixed": "df02b6dc136af45e92ee4c86f4aa6c9a60790b1e"
            },
            {
              "fixed": "bee2208276c8e0e40a249ffdcf6e5434a79a847c"
            },
            {
              "fixed": "219c87aeefdcc8c1caf28cc99e9b361ce7393d3a"
            },
            {
              "fixed": "bbe2fd6d77df630356185406a97317f6aa6a92cf"
            },
            {
              "fixed": "dc8b33b819cb02a75936940c120aa669ad89942d"
            },
            {
              "fixed": "d4e359b3608a0e184bbe8d61a5c3b50d0831c44a"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.1.0"
            },
            {
              "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-2026-90248.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_api: fix teardown of an adopted proto on insert-race loss\n\nIn tc_new_tfilter() the create branch sets tp_created = 1 before calling\ntcf_chain_tp_insert_unique(). When the caller loses the race (another\nrequest inserted a proto at the same chain/prio first), insert_unique()\ndestroys the caller's own tp_new and returns the winner's proto with an\nextra reference. tp_created was never cleared, so the loser's errout\npath treated the winner's live proto as its own and called\ntcf_chain_tp_delete_empty() on it, silently unlinking an active\nclassifier that the winning request already advertised via\nRTM_NEWTFILTER.\n\nTrack the outcome of the insert step in a single tri-state variable so\neach errout path reacts correctly:\n\n- TP_NOT_CREATED: no proto created; pursue the old path.\n- TP_CREATED: proto inserted successfully; same code path as before.\n- TP_NOT_OWNED: New - lost the insert race; tp is another request's proto\n  (chain ref already released by tp_new's destroy)\n\nBoth errout reactions are single expressions derived from the state.\n\nThis fix is motivated by the Sashiko's automated review of Patch\n(net/sched: cls_api: Always acquire rtnl_lock when destroying locked\nclassifiers) [1][2]. The review identified the silent-unlink behaviour of\nan adopted proto's teardown when a request loses the\ntcf_chain_tp_insert_unique() race.\n\n[1] https://sashiko.dev/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com\n[2] https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com",
  "id": "CVE-2026-90248",
  "modified": "2026-09-19T03:30:48.121346545Z",
  "published": "2026-09-17T16:07:50.104Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/219c87aeefdcc8c1caf28cc99e9b361ce7393d3a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a68e664ddf16ecae6d769d6a2eb356f8abab75c9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bbe2fd6d77df630356185406a97317f6aa6a92cf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bee2208276c8e0e40a249ffdcf6e5434a79a847c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d4e359b3608a0e184bbe8d61a5c3b50d0831c44a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dc8b33b819cb02a75936940c120aa669ad89942d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/df02b6dc136af45e92ee4c86f4aa6c9a60790b1e"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90248.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90248"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "net/sched: cls_api: fix teardown of an adopted proto on insert-race loss"
}