{"id":"CVE-2026-46066","state":"PUBLISHED","title":"ceph: fix num_ops off-by-one when crypto allocation fails","description":"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->num_ops`; because it doesn't follow through and\nadd the discontiguous folio to the array, ceph_submit_write() -- which\nexpects that `ceph_wbc->num_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->op_idx + 1 != req->r_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->num_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.","publishedAt":"2026-05-27T12:57:41.865Z","updatedAt":"2026-10-21T12:41:16.157Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d55207717ded95c8f2760a30e93319fa313186e6","status":"affected","lessThan":"f65a96fe2467a9b184c6ae963d95a260a202c98e","versionType":"git"},{"version":"d55207717ded95c8f2760a30e93319fa313186e6","status":"affected","lessThan":"5dd151799d826d3736ae60c2b22cbc9d96a2a613","versionType":"git"},{"version":"d55207717ded95c8f2760a30e93319fa313186e6","status":"affected","lessThan":"6200f41d6fcf2ac7e24866431e381cbc914560e4","versionType":"git"},{"version":"d55207717ded95c8f2760a30e93319fa313186e6","status":"affected","lessThan":"ba12c1e578890f6337a415b7dedf476c6d455105","versionType":"git"},{"version":"d55207717ded95c8f2760a30e93319fa313186e6","status":"affected","lessThan":"a0d9555bf9eaeba34fe6b6bb86f442fe08ba3842","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ceph/addr.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.6","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.30","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.4","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ceph/addr.c"]}],"references":["https://git.kernel.org/stable/c/f65a96fe2467a9b184c6ae963d95a260a202c98e","https://git.kernel.org/stable/c/5dd151799d826d3736ae60c2b22cbc9d96a2a613","https://git.kernel.org/stable/c/6200f41d6fcf2ac7e24866431e381cbc914560e4","https://git.kernel.org/stable/c/ba12c1e578890f6337a415b7dedf476c6d455105","https://git.kernel.org/stable/c/a0d9555bf9eaeba34fe6b6bb86f442fe08ba3842"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/46xxx/CVE-2026-46066.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-46066","state":"PUBLISHED","datePublished":"2026-05-27T12:57:41.865Z","dateUpdated":"2026-10-21T12:41:16.157Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-13T15:03:33.095Z"},"containers":{"cna":{"title":"ceph: fix num_ops off-by-one when crypto allocation fails","descriptions":[{"lang":"en","value":"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->num_ops`; because it doesn't follow through and\nadd the discontiguous folio to the array, ceph_submit_write() -- which\nexpects that `ceph_wbc->num_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->op_idx + 1 != req->r_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->num_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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d55207717ded95c8f2760a30e93319fa313186e6","status":"affected","lessThan":"f65a96fe2467a9b184c6ae963d95a260a202c98e","versionType":"git"},{"version":"d55207717ded95c8f2760a30e93319fa313186e6","status":"affected","lessThan":"5dd151799d826d3736ae60c2b22cbc9d96a2a613","versionType":"git"},{"version":"d55207717ded95c8f2760a30e93319fa313186e6","status":"affected","lessThan":"6200f41d6fcf2ac7e24866431e381cbc914560e4","versionType":"git"},{"version":"d55207717ded95c8f2760a30e93319fa313186e6","status":"affected","lessThan":"ba12c1e578890f6337a415b7dedf476c6d455105","versionType":"git"},{"version":"d55207717ded95c8f2760a30e93319fa313186e6","status":"affected","lessThan":"a0d9555bf9eaeba34fe6b6bb86f442fe08ba3842","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ceph/addr.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.6","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.30","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.4","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ceph/addr.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/f65a96fe2467a9b184c6ae963d95a260a202c98e"},{"url":"https://git.kernel.org/stable/c/5dd151799d826d3736ae60c2b22cbc9d96a2a613"},{"url":"https://git.kernel.org/stable/c/6200f41d6fcf2ac7e24866431e381cbc914560e4"},{"url":"https://git.kernel.org/stable/c/ba12c1e578890f6337a415b7dedf476c6d455105"},{"url":"https://git.kernel.org/stable/c/a0d9555bf9eaeba34fe6b6bb86f442fe08ba3842"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-21T12:41:16.157Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"6.18.30"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"7.0.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}