xprtrdma: Fix bcall rep leak and unbounded peek

{
  "id": "0109fbd94302319ccdff9b9f55491ba8e4e84ecb0a54a5310d5fbfbf4808732e",
  "url": "https://osv.dev/vulnerability/CVE-2026-72466",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "xprtrdma: Fix bcall rep leak and unbounded peek",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: xprtrdma: Fix bcall rep leak and unbounded peek rpcrdma_is_bcall() decodes a reply's first words to decide whether the frame is a backchannel call. Two issues in that decode path let a short or malformed reply leak the receive buffer and drain the Receive queue. First, the speculative peek p = xdr_inline_decode(xdr, 0); /* five p++ reads follow */ asks xdr_inline_decode() for zero bytes, which returns xdr->p without consulting xdr->end. The five subsequent __be32 reads can then walk up to 20 bytes past the wire payload into stale regbuf contents and misclassify the reply as a backchannel call. Second, after the post-peek p = xdr_inline_decode(xdr, 3 * sizeof(*p)); if (unlikely(!p)) return true; the short-header arm returns true without calling rpcrdma_bc_receive_call(). The contract with the caller is that a true return transfers ownership of rep to the backchannel path: rpcrdma_reply_handler() if (rpcrdma_is_bcall(r_xprt, rep)) return; /* bare return, skips out_post */ ... out_post: rpcrdma_post_recvs(r_xprt, credits + ...); Because rpcrdma_bc_receive_call() never ran, no one took rep, but rpcrdma_reply_handler still bare-returns past rpcrdma_rep_put() and rpcrdma_post_recvs(). The rep, with its persistently DMA-mapped receive buffer, is orphaned on rb_all_reps and freed only at transport teardown. This completion reposts nothing, so its slot is reclaimed only when a later forward-channel reply reaches out_p",
    "evidence": "osv:CVE-2026-72466",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.212",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.178",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.145",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.97",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-72466",
      "aliases": [
        "CVE-2026-72466"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "41c8f70f5a3db7e06179186b6525fd9ee1d7d314"
                },
                {
                  "fixed": "0cee8f9c3b14bd6dee9c4310090a7f45b89b834f"
                },
                {
                  "fixed": "7afc2f8d2fd9394724df9eaf22ce7a71029a5fba"
                },
                {
                  "fixed": "88b5346284a184a6b7d019912232a571d672d3e3"
                },
                {
                  "fixed": "07aa506436be7634e381e1e1f6d0efa9efc81ecc"
                },
                {
                  "fixed": "d7a2870dde3bb09d51d6b9c877642996ad6b92dd"
                },
                {
                  "fixed": "118a16a18c59f7ad8084b2d13988839b669fca10"
                },
                {
                  "fixed": "c7653d5cebc8492c77ec0415b5e9c0fb3e644bc6"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72466.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.14.0"
                },
                {
                  "fixed": "5.15.212"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.178"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.145"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.97"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.40"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.1.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72466.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.646159740Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/07aa506436be7634e381e1e1f6d0efa9efc81ecc",
        "https://git.kernel.org/stable/c/0cee8f9c3b14bd6dee9c4310090a7f45b89b834f",
        "https://git.kernel.org/stable/c/118a16a18c59f7ad8084b2d13988839b669fca10",
        "https://git.kernel.org/stable/c/7afc2f8d2fd9394724df9eaf22ce7a71029a5fba",
        "https://git.kernel.org/stable/c/88b5346284a184a6b7d019912232a571d672d3e3",
        "https://git.kernel.org/stable/c/c7653d5cebc8492c77ec0415b5e9c0fb3e644bc6",
        "https://git.kernel.org/stable/c/d7a2870dde3bb09d51d6b9c877642996ad6b92dd",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72466.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-72466",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72466.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-72466",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 504976,
  "published_at": "2026-08-15T05:57:09.847+00:00"
}