FKIE_CVE-2026-98801
Vulnerability from fkie_nvd - Published: 2026-10-18 16:17 - Updated: 2026-10-19 10:19
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 |
|---|
{
"affected": [
{
"affectedData": [
{
"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",
"version": "2bb2f5fb21b0486ff69b7b4a1fe03a760527d133",
"versionType": "git"
},
{
"lessThan": "5069ce898148bd799395c5a464e006cbb840f188",
"status": "affected",
"version": "2bb2f5fb21b0486ff69b7b4a1fe03a760527d133",
"versionType": "git"
},
{
"lessThan": "a467b05b201b5c26be52ed3081992fa9c0387648",
"status": "affected",
"version": "2bb2f5fb21b0486ff69b7b4a1fe03a760527d133",
"versionType": "git"
},
{
"lessThan": "37e02c42a00be692c06343e11779aadc45f45971",
"status": "affected",
"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"
},
{
"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"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"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)."
}
],
"id": "CVE-2026-98801",
"lastModified": "2026-10-19T10:19:44.163",
"metrics": {},
"published": "2026-10-18T16:17:34.137",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"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"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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