FKIE_CVE-2026-98592

Vulnerability from fkie_nvd - Published: 2026-10-18 16:17 - Updated: 2026-10-19 10:19
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: net: spacemit: clear TX descriptor on fragment mapping failure emac_tx_mem_map() writes TX_DESC_0_OWN into the ring descriptor for every slot beyond old_head as soon as that slot's memset()'d local copy is committed with "*tx_desc_addr = tx_desc", i.e. before the buffers for that slot have necessarily all been mapped successfully. If emac_tx_map_frag() then fails on a later fragment, the err_free_skb path calls emac_free_tx_buf() to unmap and drop the skb, but leaves the already-written descriptor memory untouched, and tx_ring->head is never advanced past old_head (the "tx_ring->head = head" store is skipped by the goto). So a slot between old_head and the rolled-back head can be left with TX_DESC_0_OWN set and buffer_addr_{1,2} pointing at DMA mappings that emac_free_tx_buf() just tore down, while software considers that slot free again. The next successful emac_tx_mem_map() call only rebuilds old_head itself; if the DMA engine auto-advances into the following descriptor once it finishes old_head's packet, it will fetch that stale, already-unmapped address. emac_tx_clean_desc() already treats emac_free_tx_buf() and clearing the descriptor as a pair when reclaiming completed descriptors; do the same in the mapping failure path.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2d14720beb58870b15a52b236c3ab0be0e06e915
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3001a103a367c6051c43aff363b6979c10e65347
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ca9986cc824f2feb79b4a83e5f6f4c24c2140448
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/spacemit/k1_emac.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ca9986cc824f2feb79b4a83e5f6f4c24c2140448",
              "status": "affected",
              "version": "bfec6d7f2001c7470c3cd261ae65a3ba8737f226",
              "versionType": "git"
            },
            {
              "lessThan": "3001a103a367c6051c43aff363b6979c10e65347",
              "status": "affected",
              "version": "bfec6d7f2001c7470c3cd261ae65a3ba8737f226",
              "versionType": "git"
            },
            {
              "lessThan": "2d14720beb58870b15a52b236c3ab0be0e06e915",
              "status": "affected",
              "version": "bfec6d7f2001c7470c3cd261ae65a3ba8737f226",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/spacemit/k1_emac.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.55",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.9",
              "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: spacemit: clear TX descriptor on fragment mapping failure\n\nemac_tx_mem_map() writes TX_DESC_0_OWN into the ring descriptor for\nevery slot beyond old_head as soon as that slot\u0027s memset()\u0027d local\ncopy is committed with \"*tx_desc_addr = tx_desc\", i.e. before the\nbuffers for that slot have necessarily all been mapped successfully.\nIf emac_tx_map_frag() then fails on a later fragment, the err_free_skb\npath calls emac_free_tx_buf() to unmap and drop the skb, but leaves\nthe already-written descriptor memory untouched, and tx_ring-\u003ehead is\nnever advanced past old_head (the \"tx_ring-\u003ehead = head\" store is\nskipped by the goto).\n\nSo a slot between old_head and the rolled-back head can be left with\nTX_DESC_0_OWN set and buffer_addr_{1,2} pointing at DMA mappings that\nemac_free_tx_buf() just tore down, while software considers that slot\nfree again. The next successful emac_tx_mem_map() call only rebuilds\nold_head itself; if the DMA engine auto-advances into the following\ndescriptor once it finishes old_head\u0027s packet, it will fetch that\nstale, already-unmapped address.\n\nemac_tx_clean_desc() already treats emac_free_tx_buf() and clearing\nthe descriptor as a pair when reclaiming completed descriptors; do\nthe same in the mapping failure path."
    }
  ],
  "id": "CVE-2026-98592",
  "lastModified": "2026-10-19T10:19:20.360",
  "metrics": {},
  "published": "2026-10-18T16:17:11.830",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2d14720beb58870b15a52b236c3ab0be0e06e915"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3001a103a367c6051c43aff363b6979c10e65347"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ca9986cc824f2feb79b4a83e5f6f4c24c2140448"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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