{"id":"CVE-2026-98801","summary":"net: restrict SO_RESERVE_MEM to TCP sockets and cap max value","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).","modified":"2026-10-19T02:47:25.444361822Z","published":"2026-10-18T15:48:47.171Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98801.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"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"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98801.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98801"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"2bb2f5fb21b0486ff69b7b4a1fe03a760527d133"},{"fixed":"492e04f9a00f3cc88a1f6899417b10f3019a624e"},{"fixed":"5069ce898148bd799395c5a464e006cbb840f188"},{"fixed":"a467b05b201b5c26be52ed3081992fa9c0387648"},{"fixed":"37e02c42a00be692c06343e11779aadc45f45971"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98801.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.12.113"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.56"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98801.json"}}],"schema_version":"1.9.0"}