ceph: fix BUG_ON in __ceph_build_xattrs_blob() due to stale blob size

{
  "id": "a64cf78cc804d4724db7a1c303242dd9b027cb9a3e083f3813614fdb283b3df9",
  "url": "https://osv.dev/vulnerability/CVE-2026-52961",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ceph: fix BUG_ON in __ceph_build_xattrs_blob() due to stale blob size",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ceph: fix BUG_ON in __ceph_build_xattrs_blob() due to stale blob size The generic/642 test-case can reproduce the kernel crash: [40243.605254] ------------[ cut here ]------------ [40243.605956] kernel BUG at fs/ceph/xattr.c:918! [40243.607142] Oops: invalid opcode: 0000 [#1] SMP PTI [40243.608067] CPU: 7 UID: 0 PID: 498762 Comm: kworker/7:1 Not tainted 7.0.0-rc7+ #3 PREEMPT(full) [40243.609700] Hardware name: QEMU Ubuntu 25.10 PC v2 (i440FX + PIIX, + 10.1 machine, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [40243.611820] Workqueue: ceph-msgr ceph_con_workfn [40243.612715] RIP: 0010:__ceph_build_xattrs_blob+0x1b8/0x1e0 [40243.613731] Code: 0f 84 82 fe ff ff e9 cf 8e 56 ff 48 8d 65 e8 31 c0 5b 41 5c 41 5d 5d 31 d2 31 c9 31 f6 31 ff 45 31 c0 45 31 c9 c3 cc cc cc cc <0f> 0b 4c 8b 62 08 41 8b 85 24 07 00 00 49 83 c4 04 41 89 44 24 fc [40243.616888] RSP: 0018:ffffcc80c4d4b688 EFLAGS: 00010287 [40243.617773] RAX: 0000000000010026 RBX: 0000000000000001 RCX: 0000000000000000 [40243.618928] RDX: ffff8a773798dee0 RSI: 0000000000000000 RDI: 0000000000000000 [40243.620158] RBP: ffffcc80c4d4b6a0 R08: 0000000000000000 R09: 0000000000000000 [40243.621573] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8a75f3b58000 [40243.622907] R13: ffff8a75f3b58000 R14: 0000000000000080 R15: 000000000000bffd [40243.624054] FS: 0000000000000000(0000) GS:ffff8a787d1b4000(0000) knlGS:0000000000000000 [40243.625331] CS: 0010 DS: 0000",
    "evidence": "osv:CVE-2026-52961",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.191",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.91",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.33",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.0.10",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-52961",
      "aliases": [
        "CVE-2026-52961"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "d93231a6bc8a452323d5fef16cca7107ce483a27"
                },
                {
                  "fixed": "0fe79375e48efee268e766c800bacbd58bed655b"
                },
                {
                  "fixed": "d161c4456672f8c431e3bdf9bea817b490d14181"
                },
                {
                  "fixed": "7eb72425c4e3234926502eb262f9d6193ccd572c"
                },
                {
                  "fixed": "d5bd8b4e39cfa8b087448adcd48088065cd629d5"
                },
                {
                  "fixed": "368d21ae9081c93497b1c8163bed3eddcb2443ff"
                },
                {
                  "fixed": "0c22d9511cbde746622f8e4c11aaa63fe76d45f9"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52961.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.0.0"
                },
                {
                  "fixed": "6.1.191"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.157"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.91"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.33"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.0.10"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52961.json"
          }
        }
      ],
      "modified": "2026-11-01T02:30:25.170542371Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0c22d9511cbde746622f8e4c11aaa63fe76d45f9",
        "https://git.kernel.org/stable/c/0fe79375e48efee268e766c800bacbd58bed655b",
        "https://git.kernel.org/stable/c/368d21ae9081c93497b1c8163bed3eddcb2443ff",
        "https://git.kernel.org/stable/c/7eb72425c4e3234926502eb262f9d6193ccd572c",
        "https://git.kernel.org/stable/c/d161c4456672f8c431e3bdf9bea817b490d14181",
        "https://git.kernel.org/stable/c/d5bd8b4e39cfa8b087448adcd48088065cd629d5",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52961.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-52961",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52961.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-52961",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 499839,
  "published_at": "2026-06-24T16:28:41.836+00:00"
}