CVE-2026-63923 (GCVE-0-2026-63923)
Vulnerability from cvelistv5
Published
2026-07-19 14:55
Modified
2026-08-05 12:37
Severity ?
8.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: octeontx2-af: validate body pcifunc in rvu_mbox_handler_rep_event_notify rvu_mbox_handler_rep_event_notify() in drivers/net/ethernet/marvell/ octeontx2/af/rvu_rep.c queues a sender-controlled REP_EVENT_NOTIFY request body verbatim, and rvu_rep_up_notify() then forwards event->pcifunc (the nested body field, distinct from the AF-normalised header pcifunc) into rvu_get_pfvf(), rvu_get_pf() and the AF->PF mailbox device index without any bounds check. A VF attached to a PF that has been put into switchdev representor mode reaches this path: the VF mailbox handler otx2_pfvf_mbox_handler() forwards every message id including MBOX_MSG_REP_EVENT_NOTIFY to AF without an allowlist, and the AF dispatcher rewrites only msg->pcifunc, leaving struct rep_event::pcifunc attacker-controlled. The sibling rvu_mbox_handler_esw_cfg() refuses requests whose header pcifunc is not rvu->rep_pcifunc; this handler has no equivalent gate. An out-of-range body pcifunc selects an &rvu->pf[]/&rvu->hwvf[] element past the allocated array and, for RVU_EVENT_MAC_ADDR_CHANGE, turns into a six-byte attacker-chosen OOB ether_addr_copy() target inside the queued worker; KASAN reports a slab-out-of-bounds write in rvu_rep_wq_handler. Reject malformed requests at the handler entry by gating on is_pf_func_valid(), which is already the canonical PF/VF range check in this driver; expose it via rvu.h so callers in rvu_rep.c can use it instead of open-coding the same range arithmetic.
References
Impacted products
Vendor Product Version
Linux Linux Version: b8fea84a0468404fe3b3327ad54d583950be9dec
Version: b8fea84a0468404fe3b3327ad54d583950be9dec
Version: b8fea84a0468404fe3b3327ad54d583950be9dec
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/marvell/octeontx2/af/rvu.c",
            "drivers/net/ethernet/marvell/octeontx2/af/rvu.h",
            "drivers/net/ethernet/marvell/octeontx2/af/rvu_rep.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4467fa514482bbce82f73788943c815f3d126ab3",
              "status": "affected",
              "version": "b8fea84a0468404fe3b3327ad54d583950be9dec",
              "versionType": "git"
            },
            {
              "lessThan": "68be0260e2a02ff9b18a8678d5f8d1715fa20138",
              "status": "affected",
              "version": "b8fea84a0468404fe3b3327ad54d583950be9dec",
              "versionType": "git"
            },
            {
              "lessThan": "2156a29aecfffa2eb7c558255690084efbe9f3b0",
              "status": "affected",
              "version": "b8fea84a0468404fe3b3327ad54d583950be9dec",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/marvell/octeontx2/af/rvu.c",
            "drivers/net/ethernet/marvell/octeontx2/af/rvu.h",
            "drivers/net/ethernet/marvell/octeontx2/af/rvu_rep.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.13"
            },
            {
              "lessThan": "6.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.12",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nocteontx2-af: validate body pcifunc in rvu_mbox_handler_rep_event_notify\n\nrvu_mbox_handler_rep_event_notify() in drivers/net/ethernet/marvell/\nocteontx2/af/rvu_rep.c queues a sender-controlled REP_EVENT_NOTIFY\nrequest body verbatim, and rvu_rep_up_notify() then forwards\nevent-\u003epcifunc (the nested body field, distinct from the\nAF-normalised header pcifunc) into rvu_get_pfvf(), rvu_get_pf() and\nthe AF-\u003ePF mailbox device index without any bounds check.\n\nA VF attached to a PF that has been put into switchdev\nrepresentor mode reaches this path: the VF mailbox handler\notx2_pfvf_mbox_handler() forwards every message id including\nMBOX_MSG_REP_EVENT_NOTIFY to AF without an allowlist, and the AF\ndispatcher rewrites only msg-\u003epcifunc, leaving struct\nrep_event::pcifunc attacker-controlled.  The sibling\nrvu_mbox_handler_esw_cfg() refuses requests whose header pcifunc\nis not rvu-\u003erep_pcifunc; this handler has no equivalent gate.\n\nAn out-of-range body pcifunc selects an \u0026rvu-\u003epf[]/\u0026rvu-\u003ehwvf[]\nelement past the allocated array and, for RVU_EVENT_MAC_ADDR_CHANGE,\nturns into a six-byte attacker-chosen OOB ether_addr_copy() target\ninside the queued worker; KASAN reports a slab-out-of-bounds write\nin rvu_rep_wq_handler.\n\nReject malformed requests at the handler entry by gating on\nis_pf_func_valid(), which is already the canonical PF/VF range check\nin this driver; expose it via rvu.h so callers in rvu_rep.c can use\nit instead of open-coding the same range arithmetic."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached through the OcteonTX2 VF\u2192PF\u2192AF PCI mailbox control path, not through packet reception or any network protocol. Exploitation requires local access to an assigned SR-IOV VF device on a Marvell OCTEONTX2/CN9K/CN10K NIC.\nAC:L - Once a VF is assigned in switchdev representor mode, the attacker fully controls the malicious `rep_event` body fields (including `pcifunc`, event flags, and MAC data) and can trigger the path deterministically via repeated mailbox messages without races or uncontrollable timing.\nPR:L - Exploitation requires control of an assigned VF (typical cloud/tenant VM or container with SR-IOV passthrough), not host root; the PF mailbox forwarder passes every VF message ID including `MBOX_MSG_REP_EVENT_NOTIFY` to AF without an allowlist or trusted-VF gate on this path.\nUI:N - No victim user action (mounting, clicking, opening files) is required; the attacker triggers the vulnerable handler directly by sending a crafted mailbox message from their VF.\nS:C - In the highest-impact deployment (SR-IOV VF assigned to an untrusted VM/container tenant), corruption occurs in the host AF driver, crossing the guest/host security boundary analogous to device-mediated VM escape rather than a same-authority local privilege change.\nC:H - An out-of-range body `pcifunc` makes `rvu_get_pfvf()` return a pointer past the allocated `rvu-\u003epf[]`/`rvu-\u003ehwvf[]` arrays, and the slab-out-of-bounds write corrupts adjacent kernel heap memory in a way that can be leveraged for arbitrary kernel memory disclosure.\nI:H - For `RVU_EVENT_MAC_ADDR_CHANGE`, the worker performs a six-byte attacker-chosen `ether_addr_copy()` to an out-of-bounds `rvu_pfvf` target, constituting an exploitable out-of-bounds kernel heap write suitable for control-flow or privilege-escalation primitives.\nA:H - The out-of-bounds heap write in `rvu_rep_wq_handler` can trigger a kernel oops/panic (as confirmed by KASAN slab-out-of-bounds reports) and can be repeated on demand to deny service to the host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:37:18.035Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4467fa514482bbce82f73788943c815f3d126ab3"
        },
        {
          "url": "https://git.kernel.org/stable/c/68be0260e2a02ff9b18a8678d5f8d1715fa20138"
        },
        {
          "url": "https://git.kernel.org/stable/c/2156a29aecfffa2eb7c558255690084efbe9f3b0"
        }
      ],
      "title": "octeontx2-af: validate body pcifunc in rvu_mbox_handler_rep_event_notify",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63923",
    "datePublished": "2026-07-19T14:55:24.985Z",
    "dateReserved": "2026-07-19T07:54:57.021Z",
    "dateUpdated": "2026-08-05T12:37:18.035Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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