{"id":"CVE-2026-46066","summary":"ceph: fix num_ops off-by-one when crypto allocation fails","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nceph: fix num_ops off-by-one when crypto allocation fails\n\nmove_dirty_folio_in_page_array() may fail if the file is encrypted, the\ndirty folio is not the first in the batch, and it fails to allocate a\nbounce buffer to hold the ciphertext. When that happens,\nceph_process_folio_batch() simply redirties the folio and flushes the\ncurrent batch -- it can retry that folio in a future batch.\n\nHowever, if this failed folio is not contiguous with the last folio that\ndid make it into the batch, then ceph_process_folio_batch() has already\nincremented `ceph_wbc-\u003enum_ops`; because it doesn't follow through and\nadd the discontiguous folio to the array, ceph_submit_write() -- which\nexpects that `ceph_wbc-\u003enum_ops` accurately reflects the number of\ncontiguous ranges (and therefore the required number of \"write extent\"\nops) in the writeback -- will panic the kernel:\n\n    BUG_ON(ceph_wbc-\u003eop_idx + 1 != req-\u003er_num_ops);\n\nThis issue can be reproduced on affected kernels by writing to\nfscrypt-enabled CephFS file(s) with a 4KiB-written/4KiB-skipped/repeat\npattern (total filesize should not matter) and gradually increasing the\nsystem's memory pressure until a bounce buffer allocation fails.\n\nFix this crash by decrementing `ceph_wbc-\u003enum_ops` back to the correct\nvalue when move_dirty_folio_in_page_array() fails, but the folio already\nstarted counting a new (i.e. still-empty) extent.\n\nThe defect corrected by this patch has existed since 2022 (see first\n`Fixes:`), but another bug blocked multi-folio encrypted writeback until\nrecently (see second `Fixes:`). The second commit made it into 6.18.16,\n6.19.6, and 7.0-rc1, unmasking the panic in those versions. This patch\ntherefore fixes a regression (panic) introduced by cac190c7674f.","modified":"2026-06-26T11:56:28.269042098Z","published":"2026-05-27T12:57:41.865Z","related":["openSUSE-SU-2026:10954-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46066.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/6200f41d6fcf2ac7e24866431e381cbc914560e4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a0d9555bf9eaeba34fe6b6bb86f442fe08ba3842"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ba12c1e578890f6337a415b7dedf476c6d455105"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46066.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46066"},{"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":"d55207717ded95c8f2760a30e93319fa313186e6"},{"fixed":"6200f41d6fcf2ac7e24866431e381cbc914560e4"},{"fixed":"ba12c1e578890f6337a415b7dedf476c6d455105"},{"fixed":"a0d9555bf9eaeba34fe6b6bb86f442fe08ba3842"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-46066.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.6.0"},{"fixed":"6.18.30"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-46066.json"}}],"schema_version":"1.7.5"}