GHSA-JH5W-4GPM-R5XW

Vulnerability from github – Published: 2026-06-24 18:32 – Updated: 2026-06-30 03:37
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

libceph: Fix potential out-of-bounds access in crush_decode()

A message of type CEPH_MSG_OSD_MAP containing a crush map with at least one bucket has two fields holding the bucket algorithm. If the values in these two fields differ, an out-of-bounds access can occur. This is the case because the first algorithm field (alg) is used to allocate the correct amount of memory for a bucket of this type, while the second algorithm field inside the bucket (b->alg) is used in the subsequent processing.

This patch fixes the issue by adding a check that compares alg and b->alg and aborts the processing in case they differ. Furthermore, b->alg is set to 0 in this case, because the destruction of the crush map also uses this field to determine the bucket type, which can again result in an out-of-bounds access when trying to free the memory pointed to by the fields of the bucket. To correctly free the memory allocated for the bucket in such a case, the corresponding call to kfree is moved from the algorithm-specific crush_destroy_bucket functions to the generic crush_destroy_bucket().

Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-52955"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-131"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-24T17:17:05Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Fix potential out-of-bounds access in crush_decode()\n\nA message of type CEPH_MSG_OSD_MAP containing a crush map with at least\none bucket has two fields holding the bucket algorithm. If the values\nin these two fields differ, an out-of-bounds access can occur. This is\nthe case because the first algorithm field (alg) is used to allocate\nthe correct amount of memory for a bucket of this type, while the second\nalgorithm field inside the bucket (b-\u003ealg) is used in the subsequent\nprocessing.\n\nThis patch fixes the issue by adding a check that compares alg and\nb-\u003ealg and aborts the processing in case they differ. Furthermore,\nb-\u003ealg is set to 0 in this case, because the destruction of the crush\nmap also uses this field to determine the bucket type, which can again\nresult in an out-of-bounds access when trying to free the memory pointed\nto by the fields of the bucket. To correctly free the memory allocated\nfor the bucket in such a case, the corresponding call to kfree is moved\nfrom the algorithm-specific crush_destroy_bucket functions to the\ngeneric crush_destroy_bucket().",
  "id": "GHSA-jh5w-4gpm-r5xw",
  "modified": "2026-06-30T03:37:11Z",
  "published": "2026-06-24T18:32:41Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52955"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-52955"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2492328"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0f3604cbe4df14c5e58288ac9f57511e726a222d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3f42508191e129ee6b5ea96578d5cab14f2a013a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4c79fc2d598694bda845b46229c9d48b65042970"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6e70ef53e818c53eab28d7b0026b7fd03dddaba5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cceb10023e76bc89f3fe9238ebd0ccab0fc7c7c5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ea0d42137f0c06da71e37ffc647aab4c5309599a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ebe76d58a48a48031b98543d86c4cd30a825b622"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fb176a99e4c1a5a8448a83d83d3606203ba81faa"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52955.json"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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