{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2"
            },
            {
              "fixed": "a9eb5c4949008034909bc34ecfa0843ecc1d0ab3"
            },
            {
              "fixed": "67cf5cdad823afb0530d6d0341fbf4ca07e93a09"
            },
            {
              "fixed": "66e20942890a383eb39b2009a2ceb4c2ebec37ef"
            },
            {
              "fixed": "c62bb00caba66e01fb578d5f0302f247dc64930a"
            },
            {
              "fixed": "dfc2a00742af4cb7251c1a8fbce4fbae3cc0de4e"
            },
            {
              "fixed": "2bc6bf70d41055377f390d06f0f3521deb62fd3b"
            },
            {
              "fixed": "55fa2c7f2b15583d1a2fe1b5abcc24377359339f"
            },
            {
              "fixed": "16cc4f5c1c4b9e45eca7f7deefa5410a292db599"
            }
          ],
          "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": "5.10.265"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.216"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.183"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.148"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.101"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.42"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68187.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nexec: fix unsigned loop counter wrap in transfer_args_to_stack()\n\nThe stop value is derived from bprm-\u003ep \u003e\u003e PAGE_SHIFT. The index variable\nis an unsigned long. If bprm-\u003ep drops below PAGE_SIZE and stop becomes\nzero the loop condition index \u003e= stop is always true.\n\nAfter the index == 0 iteration the decrement wraps to ULONG_MAX and\nbprm-\u003epage[ULONG_MAX] reads sizeof(void *) bytes in front of the array.\nThe pointer has wrapped to -1. That garbage pointer is then passed to\nkmap_local_page() and PAGE_SIZE bytes are copied from wherever that\nlands into the stack of the process being created. And the loop doesn't\nterminate either...\n\nGetting there only requires bprm-\u003ep \u003c PAGE_SIZE. On !MMU\nbprm_set_stack_limit() and bprm_hit_stack_limit() are empty. So the only\nconstraint on how far bprm-\u003ep is pushed down is valid_arg_len(), i.e.\nthat each individual string still fits in what is left.\n\nbprm-\u003ep starts at PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *) so a\nsingle argument or environment string of a little over 31 pages leaves\nit in the first page:\n\n  Oops - load access fault [#1]\n  CPU: 0 UID: 0 PID: 1 Comm: victim Not tainted 7.2.0-rc4 #1\n  epc : __memcpy+0xd4/0xf8\n   ra : transfer_args_to_stack+0xaa/0xae\n   s4 : ffffffffffffffff   s2 : 0000000000000000\n   a1 : ffffffdc98000000   a2 : 0000000000001000\n  status: 0000000a00001880 badaddr: ffffffdc98000000 cause: 0000000000000005\n  [\u003c801a5324\u003e] __memcpy+0xd4/0xf8\n  [\u003c800d5f6a\u003e] load_flat_binary+0x43a/0x65e\n  [\u003c800a2de4\u003e] bprm_execve+0x1d4/0x316\n  [\u003c800a351a\u003e] do_execveat_common+0x12e/0x138\n  [\u003c800a3d44\u003e] __riscv_sys_execve+0x38/0x4e\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nThis is an arcane bug but we should still fix it.\n\nCount down from MAX_ARG_PAGES so the loop ends when index reaches stop,\nstop == 0 included. The iterations performed are unchanged for every\nother value of stop.\n\nOnly CONFIG_MMU=n builds are affected, transfer_args_to_stack() is used\nby binfmt_flat and binfmt_elf_fdpic on nommu only.\n\nThe loop predates git history. commit 7e7ec6a93434\n(\"elf_fdpic_transfer_args_to_stack(): make it generic\") only moved it\nfrom binfmt_elf_fdpic.c into fs/exec.c and narrowed the copy to the used\npart of the first page. The condition and the decrement are unchanged\nfrom 2.6.12-rc2.",
  "id": "CVE-2026-68187",
  "modified": "2026-08-21T03:30:31.034183689Z",
  "published": "2026-08-10T11:59:59.303Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/16cc4f5c1c4b9e45eca7f7deefa5410a292db599"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2bc6bf70d41055377f390d06f0f3521deb62fd3b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/55fa2c7f2b15583d1a2fe1b5abcc24377359339f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/66e20942890a383eb39b2009a2ceb4c2ebec37ef"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/67cf5cdad823afb0530d6d0341fbf4ca07e93a09"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a9eb5c4949008034909bc34ecfa0843ecc1d0ab3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c62bb00caba66e01fb578d5f0302f247dc64930a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dfc2a00742af4cb7251c1a8fbce4fbae3cc0de4e"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68187.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68187"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "exec: fix unsigned loop counter wrap in transfer_args_to_stack()"
}