GHSA-RF74-56P2-8JQJ

Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-19 18:32
VLAI
Details

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

libceph: refresh auth->authorizer_buf{,_len} after authorizer update

ceph_x_create_authorizer() caches au->buf->vec.iov_base and au->buf->vec.iov_len in struct ceph_auth_handshake. These cached values are then used by the messenger connect code when sending the authorizer.

ceph_x_update_authorizer() can rebuild the authorizer when a newer service ticket is available. If the rebuilt authorizer no longer fits in the existing buffer, ceph_x_build_authorizer() drops its reference to au->buf and allocates a new one. If this is the final reference, ceph_buffer_put() frees the old ceph_buffer and its vec.iov_base, but auth->authorizer_buf still points at that freed memory.

A subsequent msgr1 reconnect can therefore queue the stale pointer and trigger a KASAN slab-use-after-free in _copy_from_iter() while tcp_sendmsg() copies the authorizer.

Refresh auth->authorizer_buf and auth->authorizer_buf_len after a successful authorizer rebuild so the messenger sends the current buffer.

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-2026-68156"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T13:20:01Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: refresh auth-\u003eauthorizer_buf{,_len} after authorizer update\n\nceph_x_create_authorizer() caches au-\u003ebuf-\u003evec.iov_base and\nau-\u003ebuf-\u003evec.iov_len in struct ceph_auth_handshake.  These\ncached values are then used by the messenger connect code when\nsending the authorizer.\n\nceph_x_update_authorizer() can rebuild the authorizer when a newer\nservice ticket is available.  If the rebuilt authorizer no longer\nfits in the existing buffer, ceph_x_build_authorizer() drops its\nreference to au-\u003ebuf and allocates a new one.  If this is the final\nreference, ceph_buffer_put() frees the old ceph_buffer and its\nvec.iov_base, but auth-\u003eauthorizer_buf still points at that freed\nmemory.\n\nA subsequent msgr1 reconnect can therefore queue the stale pointer\nand trigger a KASAN slab-use-after-free in _copy_from_iter() while\ntcp_sendmsg() copies the authorizer.\n\nRefresh auth-\u003eauthorizer_buf and auth-\u003eauthorizer_buf_len after a\nsuccessful authorizer rebuild so the messenger sends the current\nbuffer.",
  "id": "GHSA-rf74-56p2-8jqj",
  "modified": "2026-08-19T18:32:08Z",
  "published": "2026-08-10T15:33:38Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68156"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0060ec912292a550198d8d18ac95b433c92a7091"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2334e9997308305ee4fd508fdfe6086c4150ed60"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/26f814187abceee90dbb29a02133adb4786fbb13"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5ecfcd5c05866f185357700b81b461dae4f5ebb2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/75e82e8944ac1efe9fdb88bd2f14d9a031282bdf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/79a273df64238a4ade8b709689a78589f755b8ef"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/937d61f86d377a3aa578adae7a3dfcecdddf9d89"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9d37aec9ffe4e743dabc3f84502e9723e17a30d4"
    }
  ],
  "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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