net/smc: free stashed qentry before overwrite in REQ_ADD_LINK to ADD_LINK transition

{
  "id": "dc2db8de52e7240c1593dc635a4bc498f5cd54ace0516198f493894dd9bcb47e",
  "url": "https://osv.dev/vulnerability/CVE-2026-90108",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net/smc: free stashed qentry before overwrite in REQ_ADD_LINK to ADD_LINK transition",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net/smc: free stashed qentry before overwrite in REQ_ADD_LINK to ADD_LINK transition When smc_llc_event_handler() transitions the local LLC flow from SMC_LLC_FLOW_REQ_ADD_LINK to SMC_LLC_FLOW_ADD_LINK on arrival of an ADD_LINK request, it calls smc_llc_flow_qentry_set() unconditionally: if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_REQ_ADD_LINK) { lgr->llc_flow_lcl.type = SMC_LLC_FLOW_ADD_LINK; smc_llc_flow_qentry_set(&lgr->llc_flow_lcl, qentry); ... } A CONFIRM_LINK or ADD_LINK_CONT arriving while flow->type is SMC_LLC_FLOW_REQ_ADD_LINK is stashed into flow->qentry via the SMC_LLC_CONFIRM_LINK / SMC_LLC_ADD_LINK_CONT handler (which stores into flow->qentry for any non-NONE flow type). When the subsequent ADD_LINK arrives, the REQ_ADD_LINK branch overwrites flow->qentry with the new pointer without first freeing the stashed allocation, leaking one kmalloc object. The stashed entry has no consumer: smc_llc_wait() is only called from llc_add_link_work, which is not yet scheduled while the flow type remains REQ_ADD_LINK. No waiter is sleeping on llc_msg_waiter at this point. It is safe to unconditionally free any stashed qentry before the overwrite. Call smc_llc_flow_qentry_del() before smc_llc_flow_qentry_set() in the REQ_ADD_LINK branch. smc_llc_flow_qentry_del() already checks flow->qentry before freeing, so the normal path where no entry is stashed is a no-op.",
    "evidence": "osv:CVE-2026-90108",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.188",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.110",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.52",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-90108",
      "aliases": [
        "CVE-2026-90108"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196"
                },
                {
                  "fixed": "7dd55348c0d9399a9448847819e9f3904ae507ad"
                },
                {
                  "fixed": "056395acb7041b3a1f2baa08d89a1938a8b8776a"
                },
                {
                  "fixed": "b08aacfb226a840628151643b6a34eecf545d311"
                },
                {
                  "fixed": "0fb9a513766071ea9d5f3bf988e39241b8e9ee3b"
                },
                {
                  "fixed": "e25a602c45c76a7130878db72bcf6f76df04bf85"
                },
                {
                  "fixed": "036322025d6e440cb75fc6fecbba9a16b271a2ae"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90108.json"
          }
        },
        {
          "ranges": [
            {
              "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": "6.12.110"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.52"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90108.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:52.113028564Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/036322025d6e440cb75fc6fecbba9a16b271a2ae",
        "https://git.kernel.org/stable/c/056395acb7041b3a1f2baa08d89a1938a8b8776a",
        "https://git.kernel.org/stable/c/0fb9a513766071ea9d5f3bf988e39241b8e9ee3b",
        "https://git.kernel.org/stable/c/7dd55348c0d9399a9448847819e9f3904ae507ad",
        "https://git.kernel.org/stable/c/b08aacfb226a840628151643b6a34eecf545d311",
        "https://git.kernel.org/stable/c/e25a602c45c76a7130878db72bcf6f76df04bf85",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90108.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90108",
        "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/2026/90xxx/CVE-2026-90108.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90108",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 520933,
  "published_at": "2026-09-17T16:06:16.813+00:00"
}