{"id":"CVE-2026-90067","summary":"libceph: validate banner payload length","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: validate banner payload length\n\nWhen parsing the Ceph messenger v2 protocol banner, the `payload_len` field\nis decoded from the banner prefix. If a client sends a banner with a\n`payload_len` of 0, the kernel sets up a 0-length socket read. This\nviolates an invariant in the state machine, triggering a warning in\n`populate_in_iter()`:\n\n------------[ cut here ]------------\n!iov_iter_count(&con-\u003ev2.in_iter)\nWARNING: net/ceph/messenger_v2.c:3129 at populate_in_iter\nnet/ceph/messenger_v2.c:3129 [inline], CPU#1: kworker/1:3/5070\nWARNING: net/ceph/messenger_v2.c:3129 at ceph_con_v2_try_read+0x6634/0x6810\nnet/ceph/messenger_v2.c:3159, CPU#1: kworker/1:3/5070\n...\nCall Trace:\n \u003cTASK\u003e\n ceph_con_workfn+0x1f5/0x14a0 net/ceph/messenger.c:1575\n process_one_work kernel/workqueue.c:3322 [inline]\n process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405\n worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486\n kthread+0x388/0x470 kernel/kthread.c:436\n ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n \u003c/TASK\u003e\n\nAccording to the msgr2 protocol specification, the banner payload is\nexpected to contain at least two 64-bit integers (`server_feat` and\n`server_req_feat`). Therefore, `payload_len` must be at least 16 bytes.\n\nFix this by adding a check in `process_banner_prefix()` to reject a\n`payload_len` smaller than 16 bytes. This prevents the 0-length read and\ncorrectly aborts the connection with a protocol error.","modified":"2026-09-19T03:47:23.958339939Z","published":"2026-09-17T16:05:49.600Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90067.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/279c0852999fd2384f4a88155091a99e81f96873"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3b2e62a7655d347a845a91155610ddae11daffc6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6cf666e47f2b51d5a887ec8a3226cde951757d27"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6d1c6f228854aa89844fd0152d7ed7ac72a55e89"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c1b937ff24b19e69aa7fb1b0f46a74d4c9668692"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c77633a9595658210a6e216a071e5a396a0835a7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f374967fcdf04001c9b66df1c19106fa83cd91f7"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90067.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90067"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"cd1a677cad994021b19665ed476aea63f5d54f31"},{"fixed":"279c0852999fd2384f4a88155091a99e81f96873"},{"fixed":"6cf666e47f2b51d5a887ec8a3226cde951757d27"},{"fixed":"3b2e62a7655d347a845a91155610ddae11daffc6"},{"fixed":"c1b937ff24b19e69aa7fb1b0f46a74d4c9668692"},{"fixed":"6d1c6f228854aa89844fd0152d7ed7ac72a55e89"},{"fixed":"c77633a9595658210a6e216a071e5a396a0835a7"},{"fixed":"f374967fcdf04001c9b66df1c19106fa83cd91f7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90067.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.221"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.188"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.157"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.110"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.52"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90067.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}