FKIE_CVE-2026-97953

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-10-21 13:21
Severity
7.0 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net: stmmac: fix TX descriptor availability check for TSO traffic stmmac_tso_xmit() estimates the number of free TX descriptors required by a TSO skb as: (skb->len - proto_hdr_len) / TSO_MAX_BUFF_SIZE + 1 which assumes the payload is split into TSO_MAX_BUFF_SIZE chunks. This underestimates the descriptors actually consumed by stmmac_tso_allocator(), since each fragment is mapped individually and so it needs at least one descriptor regardless of its size. Moreover, one descriptor is used for the L2/L3/L4 headers and, when the MSS changes, one more is consumed for the MSS context descriptor. For a highly fragmented TSO skb the check can therefore pass even when the ring has too few free slots. stmmac_tso_allocator() then writes past the available descriptors, overwriting descriptors still owned by the DMA engine, corrupting the TX ring. Add stmmac_tso_get_num_desc() to compute the exact number of descriptors needed for the header, the linear payload and each fragment, plus the MSS context descriptor when required, and use it in the availability check.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/09c30547da2c45bb79f7d3adffc860af332c2d42
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5e38d732ec67a5b1f9a56e6c73add480c4b6030a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/65820fc743eae322f7f94f6a64d07861211d4b21
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c28175220f808c867d5618de8ecc6dbcc815c773
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ffa6d2481bc1c87f822ecd626561484e4ee24cef
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/stmicro/stmmac/stmmac_main.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "09c30547da2c45bb79f7d3adffc860af332c2d42",
              "status": "affected",
              "version": "f748be531d7012c456b97f66091d86b3675c5fef",
              "versionType": "git"
            },
            {
              "lessThan": "ffa6d2481bc1c87f822ecd626561484e4ee24cef",
              "status": "affected",
              "version": "f748be531d7012c456b97f66091d86b3675c5fef",
              "versionType": "git"
            },
            {
              "lessThan": "c28175220f808c867d5618de8ecc6dbcc815c773",
              "status": "affected",
              "version": "f748be531d7012c456b97f66091d86b3675c5fef",
              "versionType": "git"
            },
            {
              "lessThan": "65820fc743eae322f7f94f6a64d07861211d4b21",
              "status": "affected",
              "version": "f748be531d7012c456b97f66091d86b3675c5fef",
              "versionType": "git"
            },
            {
              "lessThan": "5e38d732ec67a5b1f9a56e6c73add480c4b6030a",
              "status": "affected",
              "version": "f748be531d7012c456b97f66091d86b3675c5fef",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/stmicro/stmmac/stmmac_main.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.7"
            },
            {
              "lessThan": "4.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: stmmac: fix TX descriptor availability check for TSO traffic\n\nstmmac_tso_xmit() estimates the number of free TX descriptors required by\na TSO skb as:\n\n\t(skb-\u003elen - proto_hdr_len) / TSO_MAX_BUFF_SIZE + 1\n\nwhich assumes the payload is split into TSO_MAX_BUFF_SIZE chunks. This\nunderestimates the descriptors actually consumed by stmmac_tso_allocator(),\nsince each fragment is mapped individually and so it needs at least one\ndescriptor regardless of its size. Moreover, one descriptor is used for\nthe L2/L3/L4 headers and, when the MSS changes, one more is consumed for\nthe MSS context descriptor.\nFor a highly fragmented TSO skb the check can therefore pass even when the\nring has too few free slots. stmmac_tso_allocator() then writes past the\navailable descriptors, overwriting descriptors still owned by the DMA\nengine, corrupting the TX ring.\nAdd stmmac_tso_get_num_desc() to compute the exact number of descriptors\nneeded for the header, the linear payload and each fragment, plus the MSS\ncontext descriptor when required, and use it in the availability check."
    }
  ],
  "id": "CVE-2026-97953",
  "lastModified": "2026-10-21T13:21:17.420",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.0,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 4.7,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-25T11:17:22.930",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/09c30547da2c45bb79f7d3adffc860af332c2d42"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5e38d732ec67a5b1f9a56e6c73add480c4b6030a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/65820fc743eae322f7f94f6a64d07861211d4b21"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c28175220f808c867d5618de8ecc6dbcc815c773"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ffa6d2481bc1c87f822ecd626561484e4ee24cef"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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