CVE-2026-46066 (GCVE-0-2026-46066)
Vulnerability from cvelistv5
Published
2026-05-27 12:57
Modified
2026-06-14 17:51
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ceph: fix num_ops off-by-one when crypto allocation fails move_dirty_folio_in_page_array() may fail if the file is encrypted, the dirty folio is not the first in the batch, and it fails to allocate a bounce buffer to hold the ciphertext. When that happens, ceph_process_folio_batch() simply redirties the folio and flushes the current batch -- it can retry that folio in a future batch. However, if this failed folio is not contiguous with the last folio that did make it into the batch, then ceph_process_folio_batch() has already incremented `ceph_wbc->num_ops`; because it doesn't follow through and add the discontiguous folio to the array, ceph_submit_write() -- which expects that `ceph_wbc->num_ops` accurately reflects the number of contiguous ranges (and therefore the required number of "write extent" ops) in the writeback -- will panic the kernel: BUG_ON(ceph_wbc->op_idx + 1 != req->r_num_ops); This issue can be reproduced on affected kernels by writing to fscrypt-enabled CephFS file(s) with a 4KiB-written/4KiB-skipped/repeat pattern (total filesize should not matter) and gradually increasing the system's memory pressure until a bounce buffer allocation fails. Fix this crash by decrementing `ceph_wbc->num_ops` back to the correct value when move_dirty_folio_in_page_array() fails, but the folio already started counting a new (i.e. still-empty) extent. The defect corrected by this patch has existed since 2022 (see first `Fixes:`), but another bug blocked multi-folio encrypted writeback until recently (see second `Fixes:`). The second commit made it into 6.18.16, 6.19.6, and 7.0-rc1, unmasking the panic in those versions. This patch therefore fixes a regression (panic) introduced by cac190c7674f.
References
Impacted products
Vendor Product Version
Linux Linux Version: d55207717ded95c8f2760a30e93319fa313186e6
Version: d55207717ded95c8f2760a30e93319fa313186e6
Version: d55207717ded95c8f2760a30e93319fa313186e6
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ceph/addr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6200f41d6fcf2ac7e24866431e381cbc914560e4",
              "status": "affected",
              "version": "d55207717ded95c8f2760a30e93319fa313186e6",
              "versionType": "git"
            },
            {
              "lessThan": "ba12c1e578890f6337a415b7dedf476c6d455105",
              "status": "affected",
              "version": "d55207717ded95c8f2760a30e93319fa313186e6",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ceph/addr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.6"
            },
            {
              "lessThan": "6.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.30",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.30",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.4",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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-\u003enum_ops`; because it doesn\u0027t 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\u0027s 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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-14T17:51:51.002Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6200f41d6fcf2ac7e24866431e381cbc914560e4"
        },
        {
          "url": "https://git.kernel.org/stable/c/ba12c1e578890f6337a415b7dedf476c6d455105"
        },
        {
          "url": "https://git.kernel.org/stable/c/a0d9555bf9eaeba34fe6b6bb86f442fe08ba3842"
        }
      ],
      "title": "ceph: fix num_ops off-by-one when crypto allocation fails",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46066",
    "datePublished": "2026-05-27T12:57:41.865Z",
    "dateReserved": "2026-05-13T15:03:33.095Z",
    "dateUpdated": "2026-06-14T17:51:51.002Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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