CVE-2025-68799 (GCVE-0-2025-68799)
Vulnerability from cvelistv5
Published
2026-01-13 15:29
Modified
2026-08-05 12:11
Severity ?
8.1 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: caif: fix integer underflow in cffrml_receive() The cffrml_receive() function extracts a length field from the packet header and, when FCS is disabled, subtracts 2 from this length without validating that len >= 2. If an attacker sends a malicious packet with a length field of 0 or 1 to an interface with FCS disabled, the subtraction causes an integer underflow. This can lead to memory exhaustion and kernel instability, potential information disclosure if padding contains uninitialized kernel memory. Fix this by validating that len >= 2 before performing the subtraction.
References
Impacted products
Vendor Product Version
Linux Linux Version: b482cd2053e3b90a7b33a78c63cdb6badf2ec383
Version: b482cd2053e3b90a7b33a78c63cdb6badf2ec383
Version: b482cd2053e3b90a7b33a78c63cdb6badf2ec383
Version: b482cd2053e3b90a7b33a78c63cdb6badf2ec383
Version: b482cd2053e3b90a7b33a78c63cdb6badf2ec383
Version: b482cd2053e3b90a7b33a78c63cdb6badf2ec383
Version: b482cd2053e3b90a7b33a78c63cdb6badf2ec383
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{
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          "programFiles": [
            "net/caif/cffrml.c"
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              "version": "6.18.3",
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              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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          "nodes": [
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              "negate": false,
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncaif: fix integer underflow in cffrml_receive()\n\nThe cffrml_receive() function extracts a length field from the packet\nheader and, when FCS is disabled, subtracts 2 from this length without\nvalidating that len \u003e= 2.\n\nIf an attacker sends a malicious packet with a length field of 0 or 1\nto an interface with FCS disabled, the subtraction causes an integer\nunderflow.\n\nThis can lead to memory exhaustion and kernel instability, potential\ninformation disclosure if padding contains uninitialized kernel memory.\n\nFix this by validating that len \u003e= 2 before performing the subtraction."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:A - The malicious CAIF frame originates from a directly connected modem or remote processor over a non-routable USB or virtio link. This makes the attacker logically adjacent rather than an arbitrary Internet host.\nAC:L - A length field of 0 or 1 deterministically triggers the underflow on FCS-disabled USB and virtio interfaces. No race, timing, or uncontrolled memory-layout condition is required.\nPR:N - The framing header is parsed before CAIF channel demultiplexing, authentication, or service-level checks. A malicious CAIF peer requires no Linux credentials or capabilities.\nUI:N - Once the CAIF interface is active, the peer can trigger the vulnerability merely by supplying a malformed frame. No victim action is required.\nS:U - The vulnerable framing code and the affected kernel memory and availability remain within the same kernel security authority. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - The underflow can expose approximately 64 KiB of newly allocated, uninitialized kernel heap as skb data, and the fix identifies possible disclosure of this padding. Conservatively, this constitutes a substantial kernel-memory disclosure.\nI:N - The skb helpers allocate sufficient capacity before extending the packet, so the bug does not create an out-of-bounds write, use-after-free, or attacker-controlled overwrite. No integrity impact is established.\nA:H - Each tiny malicious frame can force an approximately 64 KiB atomic skb expansion and unratelimited error logging. Repeated frames can cause memory exhaustion, severe resource pressure, and kernel instability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:11:33.021Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f407f1c9f45bbf5c99fd80b3f3f4a94fdbe35691"
        },
        {
          "url": "https://git.kernel.org/stable/c/c54091eec6fed19e94182aa05dd6846600a642f7"
        },
        {
          "url": "https://git.kernel.org/stable/c/785c7be6361630070790f6235b696da156ac71b3"
        },
        {
          "url": "https://git.kernel.org/stable/c/f818cd472565f8b0c2c409b040e0121c5cf8592c"
        },
        {
          "url": "https://git.kernel.org/stable/c/4ec29714aa4e0601ea29d2f02b461fc0ac92c2c3"
        },
        {
          "url": "https://git.kernel.org/stable/c/21fdcc00656a60af3c7aae2dea8dd96abd35519c"
        },
        {
          "url": "https://git.kernel.org/stable/c/8a11ff0948b5ad09b71896b7ccc850625f9878d1"
        }
      ],
      "title": "caif: fix integer underflow in cffrml_receive()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-68799",
    "datePublished": "2026-01-13T15:29:09.012Z",
    "dateReserved": "2025-12-24T10:30:51.042Z",
    "dateUpdated": "2026-08-05T12:11:33.021Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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