bpf: Copy per-CPU map value padding in copy_map_value_long()

{
  "id": "1b3fdf098e0eda562571b24099962fcc689fb2108607da31fba95f81c1443195",
  "url": "https://osv.dev/vulnerability/CVE-2026-93174",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "bpf: Copy per-CPU map value padding in copy_map_value_long()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: bpf: Copy per-CPU map value padding in copy_map_value_long() In kernel, per-CPU map elements are stored with round_up(map->value_size, 8) bytes. On UAPI lookup paths, it copies the rounded size for each CPU into a temporary buffer. However, copy_map_value_long() passes 'map->value_size' to bpf_obj_memcpy(). When the map has special fields, bpf_obj_memcpy() copies around those fields with memcpy(), and does not copy the tail padding between 'map->value_size' and round_up(map->value_size, 8). The temporary UAPI lookup buffers are allocated without __GFP_ZERO. As a result, when the per-CPU map's value size is not equal to round_up(map->value_size, 8), UAPI LOOKUP_ELEM and its variants can return stale heap contents from that padding to user space. The same issue applies to bpf_iter for per-CPU maps. Pass round_up(map->value_size, 8) to bpf_obj_memcpy() from copy_map_value_long(), so per-CPU maps both with and without special fields copy the entire per-CPU slot. Remove the now redundant round_up() from bpf_obj_memcpy()'s long_memcpy path.",
    "evidence": "osv:CVE-2026-93174",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.191",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.110",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.52",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-93174",
      "aliases": [
        "CVE-2026-93174"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "448325199f574d33824dbf9121efb03558412966"
                },
                {
                  "fixed": "e0653c8f718109d140e806daac166c43e2b2b8bd"
                },
                {
                  "fixed": "953e85da53541a8dc3e7ad4e8532f29a34a32eae"
                },
                {
                  "fixed": "003bf840ed3326bd01396ce7d5b431cef0d371e7"
                },
                {
                  "fixed": "5e9f69829835521aa2942d1d14bd0990fbc6991e"
                },
                {
                  "fixed": "ff3f22ed8d2f350b4c24ee26e33daea5f08d58ef"
                },
                {
                  "fixed": "7cf9cd98cf6f0df3befc167ca6b54c07014d71de"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93174.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.1.0"
                },
                {
                  "fixed": "6.1.191"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.157"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.110"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.52"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93174.json"
          }
        }
      ],
      "modified": "2026-11-01T02:30:24.273582935Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/003bf840ed3326bd01396ce7d5b431cef0d371e7",
        "https://git.kernel.org/stable/c/5e9f69829835521aa2942d1d14bd0990fbc6991e",
        "https://git.kernel.org/stable/c/7cf9cd98cf6f0df3befc167ca6b54c07014d71de",
        "https://git.kernel.org/stable/c/953e85da53541a8dc3e7ad4e8532f29a34a32eae",
        "https://git.kernel.org/stable/c/e0653c8f718109d140e806daac166c43e2b2b8bd",
        "https://git.kernel.org/stable/c/ff3f22ed8d2f350b4c24ee26e33daea5f08d58ef",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93174.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-93174",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93174.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-93174",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 496300,
  "published_at": "2026-09-17T16:12:03.946+00:00"
}