GHSA-5R63-PV2H-4JQG

Vulnerability from github – Published: 2026-05-08 15:31 – Updated: 2026-05-11 09:30
VLAI
Details

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

libceph: Use u32 for non-negative values in ceph_monmap_decode()

This patch fixes unnecessary implicit conversions that change signedness of blob_len and num_mon in ceph_monmap_decode(). Currently blob_len and num_mon are (signed) int variables. They are used to hold values that are always non-negative and get assigned in ceph_decode_32_safe(), which is meant to assign u32 values. Both variables are subsequently used as unsigned values, and the value of num_mon is further assigned to monmap->num_mon, which is of type u32. Therefore, both variables should be of type u32. This is especially relevant for num_mon. If the value read from the incoming message is very large, it is interpreted as a negative value, and the check for num_mon > CEPH_MAX_MON does not catch it. This leads to the attempt to allocate a very large chunk of memory for monmap, which will most likely fail. In this case, an unnecessary attempt to allocate memory is performed, and -ENOMEM is returned instead of -EINVAL.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-43405"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-908"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-08T15:16:52Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Use u32 for non-negative values in ceph_monmap_decode()\n\nThis patch fixes unnecessary implicit conversions that change signedness\nof blob_len and num_mon in ceph_monmap_decode().\nCurrently blob_len and num_mon are (signed) int variables. They are used\nto hold values that are always non-negative and get assigned in\nceph_decode_32_safe(), which is meant to assign u32 values. Both\nvariables are subsequently used as unsigned values, and the value of\nnum_mon is further assigned to monmap-\u003enum_mon, which is of type u32.\nTherefore, both variables should be of type u32. This is especially\nrelevant for num_mon. If the value read from the incoming message is\nvery large, it is interpreted as a negative value, and the check for\nnum_mon \u003e CEPH_MAX_MON does not catch it. This leads to the attempt to\nallocate a very large chunk of memory for monmap, which will most likely\nfail. In this case, an unnecessary attempt to allocate memory is\nperformed, and -ENOMEM is returned instead of -EINVAL.",
  "id": "GHSA-5r63-pv2h-4jqg",
  "modified": "2026-05-11T09:30:31Z",
  "published": "2026-05-08T15:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43405"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/08bc6173fd611ad5a40f472bf5f15b92aea0fe40"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5f2806684b05bd24d05c091083b8e2517ba8ffac"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/770444611f047dbfd4517ec0bc1b179d40c2f346"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/86f7060cd638d6eb042e8ed780fb83a59ca0dcb3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b268984ae88cb0dcd7a8e8263962c748448e26e8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ba0a4df8c563536857dcbf7b4dbd0f2a15f57ace"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ee5588e2bc41acb73f6676c0520420c107cd0140"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




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.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.