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).
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).
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Sun, 18 Oct 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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). | |
| Title | net: restrict SO_RESERVE_MEM to TCP sockets and cap max value | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-18T15:48:47.171Z
Reserved: 2026-09-25T10:25:14.370Z
Link: CVE-2026-98801
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-18T16:17:34.137
Modified: 2026-10-18T16:17:34.137
Link: CVE-2026-98801
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.