{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c"
            },
            {
              "fixed": "85479b7d65b4ebcb07fbbe57230976793974ab4a"
            },
            {
              "fixed": "1c824e7c75bb4adf19553dd4ea944a5d83096be8"
            },
            {
              "fixed": "f161be39201eb5f9b1f58fb8f90b8a9cd3931eb6"
            },
            {
              "fixed": "eab3eeb68bfc639d74f27256f05546af5c4f787d"
            },
            {
              "fixed": "c59219a6b62d74936963983e5815524c3de8dd79"
            },
            {
              "fixed": "cb8246e5846dbbe34930903a90c7a90dd8e5910b"
            },
            {
              "fixed": "7130d94846dadbb97b6b7f4d78a3a7bba6e3daa1"
            },
            {
              "fixed": "00ead17c7de137a692edee59f2772e6af687e8eb"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.9.0"
            },
            {
              "fixed": "5.10.267"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.218"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.185"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.154"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.106"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.47"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80557.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: fix OOB read in decode_watchers() via missing bounds check\n\nceph_start_decoding() validates that struct_len bytes remain in the\nbuffer after the encoding header, but accepts struct_len=0 as valid:\nceph_decode_need(p, end, 0, bad) always passes. When a malicious or\ncompromised OSD sends an obj_list_watch_response_t reply with\nstruct_len=0, ceph_start_decoding() returns success with p == end,\nleaving zero bytes guaranteed for subsequent reads.\n\nThe immediately following ceph_decode_32(p) in decode_watchers() has\nno preceding bounds check. With p == end this is a 4-byte read past\nthe validated buffer boundary. The garbage value is then passed\ndirectly to kzalloc_objs() as the watcher count.\n\nThe sibling function decode_watcher() already uses the safe variants\n(ceph_decode_copy_safe, ceph_decode_64_safe, ceph_decode_skip_32)\nafter its own ceph_start_decoding() call. decode_watchers() is the\nonly site that uses the bare variant, confirming an oversight.\n\nFix by replacing ceph_decode_32(p) with ceph_decode_32_safe(p, end,\n*num_watchers, bad), consistent with the established pattern.\n\nAttacker model: a malicious or compromised OSD in a multi-tenant Ceph\ndeployment (e.g. cloud) can trigger this against any kernel client\nthat calls CEPH_OSD_OP_LIST_WATCHERS, without any further privileges\nbeyond OSD session establishment.\n\n[ idryomov: trim changelog ]",
  "id": "CVE-2026-80557",
  "modified": "2026-08-28T03:30:54.773280090Z",
  "published": "2026-08-26T14:37:24.178Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/00ead17c7de137a692edee59f2772e6af687e8eb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1c824e7c75bb4adf19553dd4ea944a5d83096be8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7130d94846dadbb97b6b7f4d78a3a7bba6e3daa1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/85479b7d65b4ebcb07fbbe57230976793974ab4a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c59219a6b62d74936963983e5815524c3de8dd79"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cb8246e5846dbbe34930903a90c7a90dd8e5910b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eab3eeb68bfc639d74f27256f05546af5c4f787d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f161be39201eb5f9b1f58fb8f90b8a9cd3931eb6"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80557.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80557"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "libceph: fix OOB read in decode_watchers() via missing bounds check"
}