Vulnerability-Lookup

FKIE_CVE-2026-97953

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 15:18

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

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/5e38d732ec67a5b1f9a56e6c73add480c4b6030a
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/65820fc743eae322f7f94f6a64d07861211d4b21
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/c28175220f808c867d5618de8ecc6dbcc815c773
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/ffa6d2481bc1c87f822ecd626561484e4ee24cef

Impacted products

	Vendor	Product	Version

JSON

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": "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": "6.12.*",
              "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-rc3",
              "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": "2026-09-25T15:18:02.970",
  "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/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"
}

CVE-2026-97953 (GCVE-0-2026-97953)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:23 – Updated: 2026-09-25 14:41

Title

net: stmmac: fix TX descriptor availability check for TSO traffic

Summary

Severity

7 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/ffa6d2481bc1c87f8…
https://git.kernel.org/stable/c/c28175220f808c867…
https://git.kernel.org/stable/c/65820fc743eae322f…
https://git.kernel.org/stable/c/5e38d732ec67a5b1f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: f748be531d7012c456b97f66091d86b3675c5fef , < ffa6d2481bc1c87f822ecd626561484e4ee24cef (git) Affected: f748be531d7012c456b97f66091d86b3675c5fef , < c28175220f808c867d5618de8ecc6dbcc815c773 (git) Affected: f748be531d7012c456b97f66091d86b3675c5fef , < 65820fc743eae322f7f94f6a64d07861211d4b21 (git) Affected: f748be531d7012c456b97f66091d86b3675c5fef , < 5e38d732ec67a5b1f9a56e6c73add480c4b6030a (git)
Linux	Linux	Affected: 4.7 Unaffected: 0 , < 4.7 (semver) Unaffected: 6.12.111 , ≤ 6.12.* (semver) Unaffected: 6.18.53 , ≤ 6.18.* (semver) Unaffected: 7.2.7 , ≤ 7.2.* (semver) Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "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": "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": "6.12.*",
              "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-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.7",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc3",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - On a stmmac router or bridge, a remote sender\u0027s TCP segments are merged by GRO (payload left in the linear head plus up to 17 fragments) and forwarded to stmmac_tso_xmit(). Flows with different segment sizes also force an MSS context descriptor. The old check, (skb-\u003elen - proto_hdr_len)/TSO_MAX_BUFF_SIZE + 1, asks for 1 descriptor where 20 are written, so the remote packets themselves shape the skb that overruns the ring.\nAC:H - The overrun happens only when the queue is awake with stmmac_tx_avail() just under the real count (about 19 free for a 20-descriptor skb), and remotely it also needs the host to forward traffic and the ingress NIC to keep payload in the linear head. The attacker can flood toward that window and retry but cannot set ring occupancy exactly, and other traffic changes it.\nPR:N - No authentication is involved: GRO merging and IP forwarding/bridging to the stmmac egress port accept any sender\u0027s packets, and TSO is used for any forwarded GSO skb that passes stmmac_tso_valid_packet() (gso_size \u003e= 64).\nUI:N - Nobody on the target has to do anything. The attacker\u0027s own flows produce the fragmented GSO skbs and fill the TX ring during normal forwarding.\nS:U - The damage stays inside the host kernel\u0027s stmmac TX ring and its bookkeeping (tx_skbuff[], tx_skbuff_dma[]). No VM, IOMMU or sandbox boundary is crossed.\nC:L - Once cur_tx catches up with dirty_tx, later sends overwrite descriptors the DMA engine still owns. Frames can then carry the wrong buffers or buffers already released by stmmac_tx_clean(), a limited, uncontrolled leak of data from other flows or memory. It gives no arbitrary read.\nI:L - Overwritten live descriptors garble other flows\u0027 outgoing frames (payload chunks swapped into the wrong TSO frame) and corrupt the driver\u0027s per-entry skb and DMA bookkeeping. The device only reads memory for TX, so there is no general kernel memory write.\nA:H - After the extra write makes the ring look empty (cur_tx == dirty_tx), completed skbs and DMA mappings are never reclaimed and later sends overwrite in-flight descriptors, triggering WARN_ONs, a TX stall, the netdev watchdog timeout and an interface reset. The attacker can repeat this at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T14:41:44.252Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ffa6d2481bc1c87f822ecd626561484e4ee24cef"
        },
        {
          "url": "https://git.kernel.org/stable/c/c28175220f808c867d5618de8ecc6dbcc815c773"
        },
        {
          "url": "https://git.kernel.org/stable/c/65820fc743eae322f7f94f6a64d07861211d4b21"
        },
        {
          "url": "https://git.kernel.org/stable/c/5e38d732ec67a5b1f9a56e6c73add480c4b6030a"
        }
      ],
      "title": "net: stmmac: fix TX descriptor availability check for TSO traffic",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97953",
    "datePublished": "2026-09-25T10:23:00.758Z",
    "dateReserved": "2026-09-25T10:18:58.205Z",
    "dateUpdated": "2026-09-25T14:41:44.252Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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FKIE_CVE-2026-97953

CVE-2026-97953 (GCVE-0-2026-97953)

Tags

Sightings

Nomenclature

Related by attack behaviour