CVE-2026-90108 (GCVE-0-2026-90108)
Vulnerability from cvelistv5
Published
2026-09-17 16:06
Modified
2026-10-19 08:58
Severity ?
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196
Version: b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196
Version: b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196
Version: b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196
Version: b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196
Version: b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/smc/smc_llc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/smc/smc_llc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.16"
            },
            {
              "lessThan": "5.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "5.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "5.16",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
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                {
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                  "versionEndExcluding": "7.3",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: free stashed qentry before overwrite in REQ_ADD_LINK to ADD_LINK transition\n\nWhen smc_llc_event_handler() transitions the local LLC flow from\nSMC_LLC_FLOW_REQ_ADD_LINK to SMC_LLC_FLOW_ADD_LINK on arrival of an ADD_LINK\nrequest, it calls smc_llc_flow_qentry_set() unconditionally:\n\n\tif (lgr-\u003ellc_flow_lcl.type == SMC_LLC_FLOW_REQ_ADD_LINK) {\n\t\tlgr-\u003ellc_flow_lcl.type = SMC_LLC_FLOW_ADD_LINK;\n\t\tsmc_llc_flow_qentry_set(\u0026lgr-\u003ellc_flow_lcl, qentry);\n\t\t...\n\t}\n\nA CONFIRM_LINK or ADD_LINK_CONT arriving while flow-\u003etype is\nSMC_LLC_FLOW_REQ_ADD_LINK is stashed into flow-\u003eqentry via the\nSMC_LLC_CONFIRM_LINK / SMC_LLC_ADD_LINK_CONT handler (which stores into\nflow-\u003eqentry for any non-NONE flow type).  When the subsequent ADD_LINK\narrives, the REQ_ADD_LINK branch overwrites flow-\u003eqentry with the new pointer\nwithout first freeing the stashed allocation, leaking one kmalloc object.\n\nThe stashed entry has no consumer: smc_llc_wait() is only called from\nllc_add_link_work, which is not yet scheduled while the flow type remains\nREQ_ADD_LINK.  No waiter is sleeping on llc_msg_waiter at this point.\nIt is safe to unconditionally free any stashed qentry before\nthe overwrite.\n\nCall smc_llc_flow_qentry_del() before smc_llc_flow_qentry_set() in the\nREQ_ADD_LINK branch.  smc_llc_flow_qentry_del() already checks flow-\u003eqentry\nbefore freeing, so the normal path where no entry is stashed is a no-op."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:58:06.785Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/7dd55348c0d9399a9448847819e9f3904ae507ad"
        },
        {
          "url": "https://git.kernel.org/stable/c/056395acb7041b3a1f2baa08d89a1938a8b8776a"
        },
        {
          "url": "https://git.kernel.org/stable/c/b08aacfb226a840628151643b6a34eecf545d311"
        },
        {
          "url": "https://git.kernel.org/stable/c/0fb9a513766071ea9d5f3bf988e39241b8e9ee3b"
        },
        {
          "url": "https://git.kernel.org/stable/c/e25a602c45c76a7130878db72bcf6f76df04bf85"
        },
        {
          "url": "https://git.kernel.org/stable/c/036322025d6e440cb75fc6fecbba9a16b271a2ae"
        }
      ],
      "title": "net/smc: free stashed qentry before overwrite in REQ_ADD_LINK to ADD_LINK transition",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90108",
    "datePublished": "2026-09-17T16:06:16.813Z",
    "dateReserved": "2026-09-11T19:38:34.787Z",
    "dateUpdated": "2026-10-19T08:58:06.785Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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