CVE-2026-98801

Status: ReceivedUnscored—

Severity—Unscored

Exploitation probability0.17 %higher than 6% of CVEs

Active exploitationNonot in the CISA catalog

Public exploitNot knownno public code found

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.

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).

Technical details traces, logs and code from the original report

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).

CVSS

NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.17 %
Percentile among all scored CVEs: 6
Score date: 10/20/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux Kernel^AI

References

Show 4 references

Raw JSON (NVD)

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{
  "id": "CVE-2026-98801",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2bb2f5fb21b0486ff69b7b4a1fe03a760527d133",
              "lessThan": "492e04f9a00f3cc88a1f6899417b10f3019a624e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "2bb2f5fb21b0486ff69b7b4a1fe03a760527d133",
              "lessThan": "5069ce898148bd799395c5a464e006cbb840f188",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "2bb2f5fb21b0486ff69b7b4a1fe03a760527d133",
              "lessThan": "a467b05b201b5c26be52ed3081992fa9c0387648",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "2bb2f5fb21b0486ff69b7b4a1fe03a760527d133",
              "lessThan": "37e02c42a00be692c06343e11779aadc45f45971",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/core/sock.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.16"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.16",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.113",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.56",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.10",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/core/sock.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-10-18T16:17:34.137",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/37e02c42a00be692c06343e11779aadc45f45971",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/492e04f9a00f3cc88a1f6899417b10f3019a624e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5069ce898148bd799395c5a464e006cbb840f188",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a467b05b201b5c26be52ed3081992fa9c0387648",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "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->sk_forward_alloc is protected by\n  sk->sk_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 > 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 << PAGE_SHIFT) to overflow\n32-bit signed int, corrupting sk->sk_forward_alloc and\nsk->sk_reserved_mem. Using a page-aligned cap (SZ_1G) ensures that the\npage-rounded sk->sk_reserved_mem reported by getsockopt(SO_RESERVE_MEM)\ncan always be passed back to setsockopt(SO_RESERVE_MEM)."
    }
  ],
  "lastModified": "2026-10-19T10:19:44.163",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}