net: restrict SO_RESERVE_MEM to TCP sockets and cap max value

{
  "id": "bdb6c661d158341ad1c4fd80d0a1dc8fd71803062f9d81d7b2ffda4b8b1e6621",
  "url": "https://osv.dev/vulnerability/CVE-2026-98801",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net: restrict SO_RESERVE_MEM to TCP sockets and cap max value",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net: restrict SO_RESERVE_MEM to TCP sockets and cap max value Commit 2bb2f5fb21b0 (\"net: add new socket option SO_RESERVE_MEM\") and commit d00c8ee31729 (\"net: fix possible NULL deref in sock_reserve_memory\") only checked sk_has_account(sk), which is true for both TCP and UDP sockets. However, SO_RESERVE_MEM and sk_unused_reserved_mem() are currently only supported by TCP: - On UDP sockets, sk->sk_forward_alloc is protected by sk->sk_receive_queue.lock, whereas sock_reserve_memory() and sock_release_reserved_memory() only acquire lock_sock(sk). Concurrent UDP packet reception/release and setsockopt(SO_RESERVE_MEM) corrupt sk_forward_alloc and memcg accounting. - udp_rmem_release() reclaims excess sk_forward_alloc without accounting for sk_unused_reserved_mem(sk). Restrict sock_reserve_memory() to TCP sockets (sk_is_tcp(sk)) for now. Supporting SO_RESERVE_MEM for UDP (acquiring sk_receive_queue.lock and honoring sk_unused_reserved_mem() in udp_rmem_release()) can be done in a future net-next series if needed. In addition, reject val > SZ_1G with -EINVAL in sk_setsockopt(SO_RESERVE_MEM). Without an upper bound, values near INT_MAX cause sk_mem_pages(delta) and (pages << PAGE_SHIFT) to overflow 32-bit signed int, corrupting sk->sk_forward_alloc and sk->sk_reserved_mem. Using a page-aligned cap (SZ_1G) ensures that the page-rounded sk->sk_reserved_mem reported by getsockopt(SO_RESERVE_MEM) can always be passed bac",
    "evidence": "osv:CVE-2026-98801",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.113",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.56",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.10",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-98801",
      "aliases": [
        "CVE-2026-98801"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "2bb2f5fb21b0486ff69b7b4a1fe03a760527d133"
                },
                {
                  "fixed": "492e04f9a00f3cc88a1f6899417b10f3019a624e"
                },
                {
                  "fixed": "5069ce898148bd799395c5a464e006cbb840f188"
                },
                {
                  "fixed": "a467b05b201b5c26be52ed3081992fa9c0387648"
                },
                {
                  "fixed": "37e02c42a00be692c06343e11779aadc45f45971"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98801.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.12.113"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.56"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.10"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98801.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.080087138Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/37e02c42a00be692c06343e11779aadc45f45971",
        "https://git.kernel.org/stable/c/492e04f9a00f3cc88a1f6899417b10f3019a624e",
        "https://git.kernel.org/stable/c/5069ce898148bd799395c5a464e006cbb840f188",
        "https://git.kernel.org/stable/c/a467b05b201b5c26be52ed3081992fa9c0387648",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98801.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98801",
        "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/2026/98xxx/CVE-2026-98801.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98801",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 497207,
  "published_at": "2026-10-18T15:48:47.171+00:00"
}