CVE-2026-98801 (GCVE-0-2026-98801)
Vulnerability from cvelistv5
Published
2026-10-18 15:48
Modified
2026-10-19 09:25
Severity ?
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 back to setsockopt(SO_RESERVE_MEM).
References
Impacted products
Vendor Product Version
Linux Linux Version: 2bb2f5fb21b0486ff69b7b4a1fe03a760527d133
Version: 2bb2f5fb21b0486ff69b7b4a1fe03a760527d133
Version: 2bb2f5fb21b0486ff69b7b4a1fe03a760527d133
Version: 2bb2f5fb21b0486ff69b7b4a1fe03a760527d133
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/sock.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "492e04f9a00f3cc88a1f6899417b10f3019a624e",
              "status": "affected",
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              "versionType": "git"
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            {
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              "versionType": "git"
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            {
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              "versionType": "git"
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            {
              "lessThan": "37e02c42a00be692c06343e11779aadc45f45971",
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              "version": "2bb2f5fb21b0486ff69b7b4a1fe03a760527d133",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/core/sock.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.16"
            },
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              "lessThan": "5.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.113",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.56",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.113",
                  "versionStartIncluding": "5.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.56",
                  "versionStartIncluding": "5.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.10",
                  "versionStartIncluding": "5.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: restrict SO_RESERVE_MEM to TCP sockets and cap max value\n\nCommit 2bb2f5fb21b0 (\"net: add new socket option SO_RESERVE_MEM\") and\ncommit d00c8ee31729 (\"net: fix possible NULL deref in sock_reserve_memory\")\nonly checked sk_has_account(sk), which is true for both TCP and UDP\nsockets.\n\nHowever, SO_RESERVE_MEM and sk_unused_reserved_mem() are currently only\nsupported by TCP:\n- On UDP sockets, sk-\u003esk_forward_alloc is protected by\n  sk-\u003esk_receive_queue.lock, whereas sock_reserve_memory() and\n  sock_release_reserved_memory() only acquire lock_sock(sk). Concurrent\n  UDP packet reception/release and setsockopt(SO_RESERVE_MEM) corrupt\n  sk_forward_alloc and memcg accounting.\n- udp_rmem_release() reclaims excess sk_forward_alloc without\n  accounting for sk_unused_reserved_mem(sk).\n\nRestrict sock_reserve_memory() to TCP sockets (sk_is_tcp(sk)) for now.\nSupporting SO_RESERVE_MEM for UDP (acquiring sk_receive_queue.lock and\nhonoring sk_unused_reserved_mem() in udp_rmem_release()) can be done in\na future net-next series if needed.\n\nIn addition, reject val \u003e SZ_1G with -EINVAL in\nsk_setsockopt(SO_RESERVE_MEM). Without an upper bound, values near\nINT_MAX cause sk_mem_pages(delta) and (pages \u003c\u003c PAGE_SHIFT) to overflow\n32-bit signed int, corrupting sk-\u003esk_forward_alloc and\nsk-\u003esk_reserved_mem. Using a page-aligned cap (SZ_1G) ensures that the\npage-rounded sk-\u003esk_reserved_mem reported by getsockopt(SO_RESERVE_MEM)\ncan always be passed back to setsockopt(SO_RESERVE_MEM)."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:25:54.691Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/492e04f9a00f3cc88a1f6899417b10f3019a624e"
        },
        {
          "url": "https://git.kernel.org/stable/c/5069ce898148bd799395c5a464e006cbb840f188"
        },
        {
          "url": "https://git.kernel.org/stable/c/a467b05b201b5c26be52ed3081992fa9c0387648"
        },
        {
          "url": "https://git.kernel.org/stable/c/37e02c42a00be692c06343e11779aadc45f45971"
        }
      ],
      "title": "net: restrict SO_RESERVE_MEM to TCP sockets and cap max value",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98801",
    "datePublished": "2026-10-18T15:48:47.171Z",
    "dateReserved": "2026-09-25T10:25:14.370Z",
    "dateUpdated": "2026-10-19T09:25:54.691Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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