{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "6d4cc40fb5f58147defc6c0e9d86e6232fe31616"
            },
            {
              "fixed": "ff40e597d5d98c0c45a4d09df8177202fac9520e"
            },
            {
              "fixed": "a1cb727fa27c2d9c7859729cd90db7bc0f46957f"
            },
            {
              "fixed": "76395109a051b53860faaec96522ef08ae9e8e27"
            },
            {
              "fixed": "c4357ebeee63cb8da1446fc936573a34e68b0f71"
            },
            {
              "fixed": "72ce4b24676e8b3b75376c4c559dd81c1ac52d5a"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.3.0"
            },
            {
              "fixed": "6.6.157"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.110"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.51"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89902.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: Avoid preempt count underflow without probe\n\nLoongArch uses break 11 for the breakpoint placed after an instruction\nthat Kprobes executes out of line. Since userspace can issue the same\nbreak instruction, do_bp() can reach kprobe_singlestep_handler() when\nthere is no current probe.\n\nThe handler actually returns false in this case, but it first calls\npreempt_enable_no_resched(). The corresponding preempt_disable() is done\nby kprobe_breakpoint_handler() on a real Kprobe hit, so it has not run\nhere. As a result, an ordinary userspace breakpoint (code 11) underflows\nthe current task's preempt count.\n\nThis also makes in_interrupt() return true until the task schedules. One\nvisible consequence is the socket cgroup attribution: cgroup_sk_alloc()\ntreats the allocation as interrupt context and assigns the socket to the\nroot cgroup. A socket opened from the SIGTRAP handler can then avoid a\nBPF_CGROUP_INET_SOCK_CREATE policy attached to the task's own cgroup.\n\nReturn as soon as kprobe_running() reports no active probe.\n\nThe same check has appeared in [PATCH v10 2/4] of the original LoongArch\nKprobes series, but was dropped before the feature reached mainline.",
  "id": "CVE-2026-89902",
  "modified": "2026-09-18T03:31:01.568488388Z",
  "published": "2026-09-16T10:32:01.655Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/72ce4b24676e8b3b75376c4c559dd81c1ac52d5a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/76395109a051b53860faaec96522ef08ae9e8e27"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a1cb727fa27c2d9c7859729cd90db7bc0f46957f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c4357ebeee63cb8da1446fc936573a34e68b0f71"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ff40e597d5d98c0c45a4d09df8177202fac9520e"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89902.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89902"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "LoongArch: Avoid preempt count underflow without probe"
}