{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  bpf: Mark the zero register precise for a register-form NULL check  check_cond_jmp_op() accepts \"if rA \u003cop\u003e rB\" as a NULL check for a nullable pointer rA when rB is a scalar known to be zero, lifts PTR_MAYBE_NULL from rA in the corresponding branch and does not mark rB precise. Consider the following program:    r0 = bpf_get_prandom_u32();   r6 = 1;                  /* the r6 == 0 path is explored first */   if (r0 == 0) goto 1f;   r6 = 0; 1:   r0 = bpf_map_lookup_elem(map, \u00260);  /* absent, NULL at runtime */   if (r0 == r6) goto 2f;   /* taken as a NULL check for r0       */   *(u8 *)(r0 + 0);         /* verifier: map value; runtime: zero */ 2:   return 0;  The r6 == 0 path is explored first and the dereference is accepted. The r6 == 1 path is pruned at the checkpoint recorded for (1), so the comparison is never verified with a non-zero r6. At runtime a failed lookup returns NULL, NULL != 1 takes the non-NULL edge and the program dereferences a pointer that is zero.",
  "id": "DEBIAN-CVE-2026-98040",
  "modified": "2026-09-26T04:47:35.736904008Z",
  "published": "2026-09-25T11:17:32.773Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-98040"
    }
  ],
  "upstream": [
    "CVE-2026-98040"
  ]
}