CVE-2026-98043

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Don't infer non-NULL from a pointer with an unbounded offset reg_not_null() decides that a register holds a non-NULL value by looking at its type alone. For pointer types that allow arithmetic the type only guarantees a non-NULL base, in case of an unbound offset the runtime offset value might still add up to NULL. Consider the followng program: r6 = bpf_map_lookup_elem(map, &0); /* present */ if (r6 == 0) return 0; r7 = bpf_map_lookup_elem(map, &1); /* absent, NULL at runtime */ r8 = r7; r8 -= r6; /* pointer - pointer: unknown scalar, -r6 */ r8 <<= 1; r8 >>= 1; /* any non-negative offset is accepted by */ /* check_reg_sane_offset_ptr() */ r6 += r8; /* verifier: map value; runtime: zero */ if (r7 != r6) return 0; *(u8 *)(r7 + 0); /* r7 is inferred non-NULL, both are zero */ At runtime both registers are zero, the comparison is true and the load faults with NULL pointer dereference. Require the offset to be within +-BPF_MAX_VAR_OFF in reg_not_null().

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-09-25 11:17:33.090000

Last modified

2026-10-21 13:21:19.943000

View original CVE JSON

{
  "id": "CVE-2026-98043",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-25T11:17:33.090",
  "lastModified": "2026-10-21T13:21:19.943",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Don't infer non-NULL from a pointer with an unbounded offset\n\nreg_not_null() decides that a register holds a non-NULL value by\nlooking at its type alone. For pointer types that allow arithmetic the\ntype only guarantees a non-NULL base, in case of an unbound offset\nthe runtime offset value might still add up to NULL.\nConsider the followng program:\n\n  r6 = bpf_map_lookup_elem(map, &0);  /* present */\n  if (r6 == 0) return 0;\n  r7 = bpf_map_lookup_elem(map, &1);  /* absent, NULL at runtime */\n  r8 = r7;\n  r8 -= r6;     /* pointer - pointer: unknown scalar, -r6 */\n  r8 <<= 1;\n  r8 >>= 1;     /* any non-negative offset is accepted by */\n                /* check_reg_sane_offset_ptr() */\n  r6 += r8;     /* verifier: map value;    runtime: zero  */\n  if (r7 != r6) return 0;\n  *(u8 *)(r7 + 0);  /* r7 is inferred non-NULL, both are zero */\n\nAt runtime both registers are zero, the comparison is true and the\nload faults with NULL pointer dereference.\n\nRequire the offset to be within +-BPF_MAX_VAR_OFF in reg_not_null()."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "cac616db39c207dc63465a4e05c6ce0e60b2cce4",
              "lessThan": "8b414dbe97fcefd116e5a620c3bd9993014aa4ce",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "cac616db39c207dc63465a4e05c6ce0e60b2cce4",
              "lessThan": "019d845a08b8ccfe8eefaaf4bca6870f2b8c58ae",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "cac616db39c207dc63465a4e05c6ce0e60b2cce4",
              "lessThan": "65bea674f43c09c0eda033a140dfac6a2842a19f",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "cac616db39c207dc63465a4e05c6ce0e60b2cce4",
              "lessThan": "cb6642048739bf4ee5aa09fe465511f1e87caa63",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "cac616db39c207dc63465a4e05c6ce0e60b2cce4",
              "lessThan": "67b529f521a6676cdfc78b91b0217d7eaa84216b",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "5.8",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "5.8",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.160",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.114",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.57",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.7",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/019d845a08b8ccfe8eefaaf4bca6870f2b8c58ae",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/65bea674f43c09c0eda033a140dfac6a2842a19f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/67b529f521a6676cdfc78b91b0217d7eaa84216b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8b414dbe97fcefd116e5a620c3bd9993014aa4ce",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cb6642048739bf4ee5aa09fe465511f1e87caa63",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}