GHSA-XP7J-G6R9-V9RW

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-10-30 15:33
VLAI
Details

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

svcrdma: Reject inline replies that overflow the pull-up buffer

An RPC-over-RDMA client can request a reply, such as an NFS READ payload, without providing a Write list or a Reply chunk to carry it. When such a reply needs more scatter/gather entries than the device's Send Queue supports, svc_rdma_pull_up_needed() selects pull-up and svc_rdma_pull_up_reply_msg() linearizes the whole reply into sctxt->sc_xprt_buf. That buffer is only sc_max_req_size bytes, while the reply on this path is bounded only by the client's request, so svc_rdma_xb_linearize() copies past the end of the buffer and corrupts adjacent slab memory. The oversized length is then stored in sc_sges[0].length and posted, so the device also reads beyond the mapped region.

The SGE-exhaustion branch is the only pull-up path that can exceed the buffer: the threshold branch pulls up only replies smaller than RPCRDMA_PULLUP_THRESH, and replies that fit the device's SGE budget are sent directly without linearization. Make svc_rdma_pull_up_needed() report -E2BIG when the reply it would pull up cannot fit sc_max_req_size, and fail the request with ERR_CHUNK as RFC 8166 Section 4.5.3 directs rather than dropping the connection.

The helper no longer answers a simple yes/no question: it now reports pull-up, no pull-up, or -E2BIG for a reply too large to linearize. Rename svc_rdma_pull_up_needed() to svc_rdma_check_pull_up() so its name no longer implies a boolean predicate.

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-2026-89530"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:35Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsvcrdma: Reject inline replies that overflow the pull-up buffer\n\nAn RPC-over-RDMA client can request a reply, such as an NFS READ\npayload, without providing a Write list or a Reply chunk to carry\nit. When such a reply needs more scatter/gather entries than the\ndevice\u0027s Send Queue supports, svc_rdma_pull_up_needed() selects\npull-up and svc_rdma_pull_up_reply_msg() linearizes the whole\nreply into sctxt-\u003esc_xprt_buf. That buffer is only sc_max_req_size\nbytes, while the reply on this path is bounded only by the client\u0027s\nrequest, so svc_rdma_xb_linearize() copies past the end of the\nbuffer and corrupts adjacent slab memory. The oversized length is\nthen stored in sc_sges[0].length and posted, so the device also\nreads beyond the mapped region.\n\nThe SGE-exhaustion branch is the only pull-up path that can exceed\nthe buffer: the threshold branch pulls up only replies smaller\nthan RPCRDMA_PULLUP_THRESH, and replies that fit the device\u0027s SGE\nbudget are sent directly without linearization. Make\nsvc_rdma_pull_up_needed() report -E2BIG when the reply it would\npull up cannot fit sc_max_req_size, and fail the request with\nERR_CHUNK as RFC 8166 Section 4.5.3 directs rather than dropping\nthe connection.\n\nThe helper no longer answers a simple yes/no question: it now\nreports pull-up, no pull-up, or -E2BIG for a reply too large to\nlinearize. Rename svc_rdma_pull_up_needed() to\nsvc_rdma_check_pull_up() so its name no longer implies a boolean\npredicate.",
  "id": "GHSA-xp7j-g6r9-v9rw",
  "modified": "2026-10-30T15:33:20Z",
  "published": "2026-09-11T21:31:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89530"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0fbe20dfe74b783d255bf389a6ea77aa25dc7860"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1949dd1576f7a8aa161b1330c6125df9d53046d5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8068358f445a11296328ffa7c524701596814a17"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8ec60eb51fae37cd3d334ff26e4a7d6fb21ff7cf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b73011049dbe909f73fd9620d94ef1757d7af2eb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fcd91b9957462d398792201c239dffaeff1cc8b2"
    }
  ],
  "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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