{"id":"CVE-2026-99139","revision":"7c53aa21ed52430e945e2b8dbd0500e2","records":[{"revision":"7c53aa21ed52430e945e2b8dbd0500e2","observedAt":"2026-10-28T11:27:43.363+00:00","statement":{"source":"cve-program","id":"CVE-2026-99139","aliases":[],"title":"tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)\n\ndo_tcp_getsockopt() reads icsk->icsk_ca_ops->name without holding\nrcu_read_lock(). Since commit 0baf26b0fcd7 (\"bpf: tcp: Support\ntcp_congestion_ops in bpf\"), icsk_ca_ops can point to dynamically\nallocated BPF struct_ops memory that may be freed concurrently via\nsetsockopt(TCP_CONGESTION), leading to a use-after-free.\n\n  BUG: KASAN: slab-use-after-free in _copy_to_user+0x37/0x60\n  Read of size 16 at addr ffff888013505260 by task exploit/149\n   _copy_to_user+0x37/0x60\n   do_tcp_getsockopt+0x158a/0x2460 (net/ipv4/tcp.c:4585)\n   tcp_getsockopt+0x91/0xf0\n   __sys_getsockopt+0xf7/0x170\n\nFix this by holding rcu_read_lock() around the ca_ops->name access,\nusing READ_ONCE() to load icsk_ca_ops, and copying the name to a\nstack buffer before releasing the lock. Also annotate the relevant\nicsk_ca_ops stores with WRITE_ONCE() to fix the accompanying KCSAN\ndata-race issue.","state":0,"publishedAt":"2026-10-28T10:34:50.674+00:00","modifiedAt":"2026-10-28T10:34:50.674+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv4/tcp.c\",\n                        \"net/ipv4/tcp_cong.c\",\n                        \"net/ipv4/tcp_dctcp.c\",\n                        \"net/ipv4/tcp_minisocks.c\",\n                        \"net/ipv4/tcp_output.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2\",\n                            \"lessThan\": \"c1804ef016392dd91267d2207ee43b1de34302ca\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2\",\n                            \"lessThan\": \"a8e45471afa230c1431c26c8e99ec24377e3b514\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2\",\n                            \"lessThan\": \"5271b79b7ad68dcb222e893773f92bdabf7750f3\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv4/tcp.c\",\n                        \"net/ipv4/tcp_cong.c\",\n                        \"net/ipv4/tcp_dctcp.c\",\n                        \"net/ipv4/tcp_minisocks.c\",\n                        \"net/ipv4/tcp_output.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.6\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.6\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.59\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.13\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/c1804ef016392dd91267d2207ee43b1de34302ca","https://git.kernel.org/stable/c/a8e45471afa230c1431c26c8e99ec24377e3b514","https://git.kernel.org/stable/c/5271b79b7ad68dcb222e893773f92bdabf7750f3"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99139","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-99139","identifiers":["CVE-2026-99139"]},"retained":false,"historicalAffected":[]}],"coverage":[]}