{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.187-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.101-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.1.6-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux-6.12"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.101-1~deb12u1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  exec: fix unsigned loop counter wrap in transfer_args_to_stack()  The stop value is derived from bprm-\u003ep \u003e\u003e PAGE_SHIFT. The index variable is an unsigned long. If bprm-\u003ep drops below PAGE_SIZE and stop becomes zero the loop condition index \u003e= stop is always true.  After the index == 0 iteration the decrement wraps to ULONG_MAX and bprm-\u003epage[ULONG_MAX] reads sizeof(void *) bytes in front of the array. The pointer has wrapped to -1. That garbage pointer is then passed to kmap_local_page() and PAGE_SIZE bytes are copied from wherever that lands into the stack of the process being created. And the loop doesn't terminate either...  Getting there only requires bprm-\u003ep \u003c PAGE_SIZE. On !MMU bprm_set_stack_limit() and bprm_hit_stack_limit() are empty. So the only constraint on how far bprm-\u003ep is pushed down is valid_arg_len(), i.e. that each individual string still fits in what is left.  bprm-\u003ep starts at PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *) so a single argument or environment string of a little over 31 pages leaves it in the first page:    Oops - load access fault [#1]   CPU: 0 UID: 0 PID: 1 Comm: victim Not tainted 7.2.0-rc4 #1   epc : __memcpy+0xd4/0xf8    ra : transfer_args_to_stack+0xaa/0xae    s4 : ffffffffffffffff   s2 : 0000000000000000    a1 : ffffffdc98000000   a2 : 0000000000001000   status: 0000000a00001880 badaddr: ffffffdc98000000 cause: 0000000000000005   [\u003c801a5324\u003e] __memcpy+0xd4/0xf8   [\u003c800d5f6a\u003e] load_flat_binary+0x43a/0x65e   [\u003c800a2de4\u003e] bprm_execve+0x1d4/0x316   [\u003c800a351a\u003e] do_execveat_common+0x12e/0x138   [\u003c800a3d44\u003e] __riscv_sys_execve+0x38/0x4e   Kernel panic - not syncing: Fatal exception in interrupt  This is an arcane bug but we should still fix it.  Count down from MAX_ARG_PAGES so the loop ends when index reaches stop, stop == 0 included. The iterations performed are unchanged for every other value of stop.  Only CONFIG_MMU=n builds are affected, transfer_args_to_stack() is used by binfmt_flat and binfmt_elf_fdpic on nommu only.  The loop predates git history. commit 7e7ec6a93434 (\"elf_fdpic_transfer_args_to_stack(): make it generic\") only moved it from binfmt_elf_fdpic.c into fs/exec.c and narrowed the copy to the used part of the first page. The condition and the decrement are unchanged from 2.6.12-rc2.",
  "id": "DEBIAN-CVE-2026-68187",
  "modified": "2026-09-14T16:47:31.393543731Z",
  "published": "2026-08-10T13:20:05.870Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-68187"
    }
  ],
  "upstream": [
    "CVE-2026-68187"
  ]
}