{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "78147ca8b4a9b6cf0e597ddd6bf17959e08376c2"
            },
            {
              "fixed": "1e2e3481e39103a386b86be1c33eaef97cbdf16e"
            },
            {
              "fixed": "3a78b841879c2a3243f74edc514236fb2907167f"
            },
            {
              "fixed": "06d0390c37fa6714624af771bd72bbf1a7ed9bb1"
            },
            {
              "fixed": "9c5a03c3dc505c0295339b0a1b9e4fe36447e482"
            },
            {
              "fixed": "a1c954ca4977a4e6ec73ef92fe48073ec54f9fc8"
            },
            {
              "fixed": "6d33a7e6bf6c6b293a266a617201285a1ad32c56"
            },
            {
              "fixed": "b7713a784c59515d0aba558c8f5df6a0164dd3a9"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.221"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.188"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.157"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.109"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.50"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89532.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsvcrdma: Fix pcl_for_each_segment for empty chunks\n\nWhen a parsed chunk list contains a chunk whose ch_segcount is zero,\npcl_for_each_segment computes its inclusive upper bound as\n\u0026chunk-\u003ech_segments[ch_segcount - 1]. ch_segcount is u32, so the\nsubtraction wraps to 0xFFFFFFFF and the bound lands far past the\nch_segments flex array. The loop body then walks unrelated memory at\nsizeof(struct svc_rdma_segment) stride until it faults.\n\nA zero-segcount chunk is reachable from the wire:\nxdr_check_write_chunk() only rejects segcount values greater than\nrc_maxpages, and pcl_alloc_write() links a freshly allocated chunk\nonto rc_write_pcl/rc_reply_pcl before its segment-fill loop runs,\nso a Write or Reply chunk advertising zero segments leaves\nch_segcount == 0 on the list. When the transport has negotiated\nSend-With-Invalidate, svc_rdma_get_inv_rkey() iterates all four\nPCLs with pcl_for_each_segment and dereferences segment-\u003ers_handle\non each iteration, turning the underflow into an out-of-bounds read\nand a general protection fault.\n\n    xdr_check_write_list / xdr_check_reply_chunk\n      pcl_alloc_write()\n        chunk = pcl_alloc_chunk(...)  /* ch_segcount = 0 */\n        list_add_tail(\u0026chunk-\u003ech_list, \u0026pcl-\u003ecl_chunks)\n        /* fill loop iterates zero times for wire segcount 0 */\n\n    svc_rdma_get_inv_rkey()\n      pcl_for_each_chunk(rc_write_pcl)\n        pcl_for_each_segment(segment, chunk)\n          pos \u003c= \u0026ch_segments[0u - 1u]  /* 0xFFFFFFFF */\n          segment-\u003ers_handle            /* OOB read -\u003e GPF */\n\nFix by switching the macro to a half-open upper bound that uses\nch_segcount directly. For ch_segcount == 0 the loop start equals the\nloop end and the body is skipped; for ch_segcount \u003e 0 the iteration\nrange is unchanged. All six existing call sites in\nnet/sunrpc/xprtrdma/svc_rdma_recvfrom.c and\nnet/sunrpc/xprtrdma/svc_rdma_rw.c remain correct under the new bound,\nso no caller changes are needed.",
  "id": "CVE-2026-89532",
  "modified": "2026-09-15T03:31:06.181434483Z",
  "published": "2026-09-11T19:44:11.495Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/06d0390c37fa6714624af771bd72bbf1a7ed9bb1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1e2e3481e39103a386b86be1c33eaef97cbdf16e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3a78b841879c2a3243f74edc514236fb2907167f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6d33a7e6bf6c6b293a266a617201285a1ad32c56"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9c5a03c3dc505c0295339b0a1b9e4fe36447e482"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a1c954ca4977a4e6ec73ef92fe48073ec54f9fc8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b7713a784c59515d0aba558c8f5df6a0164dd3a9"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89532.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89532"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "svcrdma: Fix pcl_for_each_segment for empty chunks"
}