{"id":"CVE-2026-63979","revision":"b89cca39dfae4b1ab49398564965cd9f","records":[{"revision":"b89cca39dfae4b1ab49398564965cd9f","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-63979","aliases":[],"title":"net/handshake: hand off the pinned file reference to accept_doit","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/handshake: hand off the pinned file reference to accept_doit\n\nhandshake_req_next() removes the request from the per-net\npending list and drops hn_lock before handshake_nl_accept_doit()\nreads req->hr_sk->sk_socket and dereferences sock->file (once in\nFD_PREPARE() and again in get_file()).  In that window a\nconsumer running tls_handshake_cancel() followed by sockfd_put()\n(svc_sock_free) or __fput_sync() (xs_reset_transport) releases\nsock->file.  sock_release() then runs sock_orphan(), zeroing\nsk_socket, and frees the struct socket.  The accept-side code\neither reads NULL through sk_socket or chases freed memory.\n\nThe submit-side sock_hold() does not prevent this.  sk_refcnt\nprotects struct sock, but struct socket and sock->file are\nindependently refcounted via the file descriptor the consumer\nowns.  Pinning sk leaves sock and sock->file unprotected.\n\nRetarget the accept-side dereferences at req->hr_file, which was\npinned at submit time, instead of req->hr_sk->sk_socket->file.\nPinning on its own is not sufficient: a consumer that cancels\nbetween handshake_req_next() returning and accept_doit reaching\nFD_PREPARE() takes the !remove_pending() branch in\nhandshake_req_cancel() and drops hr_file before the accept side\ntakes its own reference.  Hand off an additional file reference\ninside handshake_req_next(), under hn_lock, so the accept side\noperates on a reference that no concurrent handshake_req_cancel()\ncan revoke.  FD_PREPARE() consumes that handed-off reference,\neither by transferring it to the new fd in fd_publish() or by\ndropping it in the cleanup destructor on error; the explicit\nget_file() that previously balanced FD_PREPARE() is therefore\nredundant and goes away.\n\nUpdate handshake_req_cancel_test2 and _test3 to simulate the\nFD_PREPARE() consumption with an fput() so the kunit file-count\nassertions stay balanced.","state":0,"publishedAt":"2026-07-19T14:56:03.177+00:00","modifiedAt":"2026-10-21T12:42:50.338+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/handshake/handshake-test.c\",\n                        \"net/handshake/netlink.c\",\n                        \"net/handshake/request.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3b3009ea8abb713b022d94fba95ec270cf6e7eae\",\n                            \"lessThan\": \"b869e3e4ce1996df23b3efdbbe9a64c4ab81d745\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3b3009ea8abb713b022d94fba95ec270cf6e7eae\",\n                            \"lessThan\": \"2f28dbb30b88eafab8d49aaec94710b4e12dea8e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3b3009ea8abb713b022d94fba95ec270cf6e7eae\",\n                            \"lessThan\": \"68eba6519cbd6359fb554a9720f3a3b6b2eba23f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3b3009ea8abb713b022d94fba95ec270cf6e7eae\",\n                            \"lessThan\": \"c06876d4fac38f35820946ee3b1be7d7da799cd4\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3b3009ea8abb713b022d94fba95ec270cf6e7eae\",\n                            \"lessThan\": \"f4251190e58b209999c1ba9e6d2976136a1be055\",\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/handshake/handshake-test.c\",\n                        \"net/handshake/netlink.c\",\n                        \"net/handshake/request.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.4\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.4\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.160\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.114\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.44\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.0.12\",\n                            \"lessThanOrEqual\": \"7.0.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/b869e3e4ce1996df23b3efdbbe9a64c4ab81d745","https://git.kernel.org/stable/c/2f28dbb30b88eafab8d49aaec94710b4e12dea8e","https://git.kernel.org/stable/c/68eba6519cbd6359fb554a9720f3a3b6b2eba23f","https://git.kernel.org/stable/c/c06876d4fac38f35820946ee3b1be7d7da799cd4","https://git.kernel.org/stable/c/f4251190e58b209999c1ba9e6d2976136a1be055"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-63979","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-63979","identifiers":["CVE-2026-63979"]},"retained":false,"historicalAffected":[]}],"coverage":[]}