CVE-2024-56563 (GCVE-0-2024-56563)
Vulnerability from cvelistv5
Published
2024-12-27 14:23
Modified
2026-08-05 11:45
Summary
In the Linux kernel, the following vulnerability has been resolved: ceph: fix cred leak in ceph_mds_check_access() get_current_cred() increments the reference counter, but the put_cred() call was missing.
Impacted products
Vendor Product Version
Linux Linux Version: 596afb0b8933ba6ed7227adcc538db26feb25c74
Version: 596afb0b8933ba6ed7227adcc538db26feb25c74
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Show details on NVD website


{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ceph/mds_client.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e3d1c9e2b811f13bdbbb962c2b17a6091c28522c",
              "status": "affected",
              "version": "596afb0b8933ba6ed7227adcc538db26feb25c74",
              "versionType": "git"
            },
            {
              "lessThan": "c5cf420303256dcd6ff175643e9e9558543c2047",
              "status": "affected",
              "version": "596afb0b8933ba6ed7227adcc538db26feb25c74",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ceph/mds_client.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.10"
            },
            {
              "lessThan": "6.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.4",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.13",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: fix cred leak in ceph_mds_check_access()\n\nget_current_cred() increments the reference counter, but the\nput_cred() call was missing."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The leak is triggered by ordinary local VFS syscalls (`open`, `creat`, `unlink`, `chmod`, `truncate`) issued against a mounted CephFS; no network peer input reaches the vulnerable function directly.\nAC:L - The missing `put_cred()` is unconditional \u2014 every single call to `ceph_mds_check_access()` leaks a reference with no race, timing window, or special configuration required, so a trivial loop drives the leak deterministically.\nPR:L - Any unprivileged local user with access to a path on an already-mounted CephFS can trigger it; the call sites in `ceph_open()`/`ceph_atomic_open()`/`ceph_unlink()`/`__ceph_setattr() ` are reached before any capability or auth gate.\nUI:N - No action by another user is needed \u2014 the attacker triggers the leak entirely on their own via normal file operations on the existing mount.\nS:U - The leaked credentials and any resulting corruption stay within the kernel\u0027s own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The leaked object is `struct cred`, incremented through an unchecked `atomic_long_add()` with no `refcount_t` saturation; on 32-bit builds the counter wraps at 2^32, freeing a live credential structure and yielding a use-after-free read primitive over uid/gid/capability fields.\nI:H - The same credential refcount imbalance/overflow permits a freed `cred` to be reallocated and overwritten by attacker-controlled heap content \u2014 the classic CVE-2016-0728-style path to arbitrary modification of `cap_effective`/`euid` and full local privilege escalation.\nA:H - Each operation permanently pins a `cred` plus its `user_struct`, `user_namespace`, `ucounts`, `group_info` and keyrings, so an unprivileged loop produces an unbounded, unreclaimable kernel memory leak ending in OOM, and the 32-bit refcount wrap causes an outright UAF crash."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T11:45:07.489Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e3d1c9e2b811f13bdbbb962c2b17a6091c28522c"
        },
        {
          "url": "https://git.kernel.org/stable/c/c5cf420303256dcd6ff175643e9e9558543c2047"
        }
      ],
      "title": "ceph: fix cred leak in ceph_mds_check_access()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2024-56563",
    "datePublished": "2024-12-27T14:23:07.854Z",
    "dateReserved": "2024-12-27T14:03:05.994Z",
    "dateUpdated": "2026-08-05T11:45:07.489Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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