{"id":"CVE-2026-80561","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-80561","summary":"libceph: fix multiple unsafe decodes in decode_locker()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: fix multiple unsafe decodes in decode_locker()\n\ndecode_locker() in cls_lock_client.c contains three unsafe decode\noperations that allow a malicious or compromised OSD to trigger\nslab-out-of-bounds reads:\n\n1. ceph_decode_copy() at the locker_id_t name field has no preceding\n   bounds check. With p == end after ceph_start_decoding() accepts\n   struct_len=0, this reads sizeof(ceph_entity_name) = 9 bytes past\n   the validated buffer boundary.\n\n2. *p += sizeof(struct ceph_timespec) after the locker_info_t header\n   is an unchecked pointer advance. A malicious OSD can position p\n   past end, causing all subsequent _safe checks to pass against a\n   bogus boundary.\n\n3. len = ceph_decode_32(p) has no preceding bounds check, and the\n   immediately following *p += len is uncapped. A malicious OSD can\n   send len=0xffffffff, advancing p gigabytes past end and escaping\n   the decode window entirely.\n\nFix all three by replacing bare operations with their safe variants:\n  ceph_decode_copy   -> ceph_decode_copy_safe\n  *p += sizeof(...)  -> ceph_decode_skip_n\n  ceph_decode_32(p)  -> ceph_decode_32_safe\n  *p += len          -> ceph_decode_skip_n\n\nA new label is added to return -EINVAL on any bounds violation.\n-EINVAL is appropriate here: the data received from the OSD\nis structurally malformed, which is an invalid argument to the decode\ncontract regardless of whether the caller or the wire is at fault.\n\nAttacker model: a malicious or compromised OSD in a multi-tenant Ceph\ndeployment can trigger this against any kernel client that issues the\nlock.get_info class method (e.g. during RBD exclusive lock acquisition)\nwithout any further privileges beyond OSD session establishment.\n\n[ idryomov: use ceph_decode_skip_string() to skip description, trim\n  changelog ]","published":"2026-08-26T14:37:26.572Z","modified":"2026-08-28T03:47:29.300488918Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"5.10.266"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1ed45c8d96498725eb54f740172f9068d8673906"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3c3716dc06a34e4ca7f743f5fcfa07fbc5a11070"},{"type":"WEB","url":"https://git.kernel.org/stable/c/437b6551cfcc235eea1d735a874f9d421f555e17"},{"type":"WEB","url":"https://git.kernel.org/stable/c/51c8d238fe7236de627ab1a1433694552a904136"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6265103e78f0ee7e2518de9cf938b94bee9700a0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d1bba38574d095f191557d397d9633f08cd966b1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/dbfd83f722a78446ec18a476ef7a38e52240b50a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fa4aa86fff0c56799c2e3f51a88879053285f4a9"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80561.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80561"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-28T03:47:29.300488918Z"}}