GHSA-4VP5-JWR6-3Q9M
Vulnerability from github – Published: 2026-10-18 18:32 – Updated: 2026-10-18 18:32In 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).
{
"affected": [],
"aliases": [
"CVE-2026-98801"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-10-18T16:17:34Z",
"severity": null
},
"details": "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).",
"id": "GHSA-4vp5-jwr6-3q9m",
"modified": "2026-10-18T18:32:04Z",
"published": "2026-10-18T18:32:04Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98801"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/37e02c42a00be692c06343e11779aadc45f45971"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/492e04f9a00f3cc88a1f6899417b10f3019a624e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5069ce898148bd799395c5a464e006cbb840f188"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a467b05b201b5c26be52ed3081992fa9c0387648"
}
],
"schema_version": "1.4.0",
"severity": []
}
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