{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2026-31649",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-31649",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-04-24T14:45:02.520Z",
    "updatedAt": "2026-10-19T18:56:01.547Z",
    "importedAt": "2026-10-24T01:58:02.025Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "net: stmmac: fix integer underflow in chain mode",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: stmmac: fix integer underflow in chain mode\n\nThe jumbo_frm() chain-mode implementation unconditionally computes\n\n    len = nopaged_len - bmax;\n\nwhere nopaged_len = skb_headlen(skb) (linear bytes only) and bmax is\nBUF_SIZE_8KiB or BUF_SIZE_2KiB.  However, the caller stmmac_xmit()\ndecides to invoke jumbo_frm() based on skb->len (total length including\npage fragments):\n\n    is_jumbo = stmmac_is_jumbo_frm(priv, skb->len, enh_desc);\n\nWhen a packet has a small linear portion (nopaged_len <= bmax) but a\nlarge total length due to page fragments (skb->len > bmax), the\nsubtraction wraps as an unsigned integer, producing a huge len value\n(~0xFFFFxxxx).  This causes the while (len != 0) loop to execute\nhundreds of thousands of iterations, passing skb->data + bmax * i\npointers far beyond the skb buffer to dma_map_single().  On IOMMU-less\nSoCs (the typical deployment for stmmac), this maps arbitrary kernel\nmemory to the DMA engine, constituting a kernel memory disclosure and\npotential memory corruption from hardware.\n\nFix this by introducing a buf_len local variable clamped to\nmin(nopaged_len, bmax).  Computing len = nopaged_len - buf_len is then\nalways safe: it is zero when the linear portion fits within a single\ndescriptor, causing the while (len != 0) loop to be skipped naturally,\nand the fragment loop in stmmac_xmit() handles page fragments afterward.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "286a837217204b1ef105e3a554d0757e4fdfaac1",
              "status": "affected",
              "versionType": "git",
              "lessThan": "513e06735f5be575b409d195822195348b164e48"
            },
            {
              "version": "286a837217204b1ef105e3a554d0757e4fdfaac1",
              "status": "affected",
              "versionType": "git",
              "lessThan": "275bdf762e82082f064e60a92448fa2ac43cf95b"
            },
            {
              "version": "286a837217204b1ef105e3a554d0757e4fdfaac1",
              "status": "affected",
              "versionType": "git",
              "lessThan": "a2b68a9a476b9544ff31f1fbcd5d80867a8a5e2f"
            },
            {
              "version": "286a837217204b1ef105e3a554d0757e4fdfaac1",
              "status": "affected",
              "versionType": "git",
              "lessThan": "b7b8012193fd98236d7ae05d4b553f010a77b2ef"
            },
            {
              "version": "286a837217204b1ef105e3a554d0757e4fdfaac1",
              "status": "affected",
              "versionType": "git",
              "lessThan": "2c91b39912278d0878f9ba60ba04d2518b18a08d"
            },
            {
              "version": "286a837217204b1ef105e3a554d0757e4fdfaac1",
              "status": "affected",
              "versionType": "git",
              "lessThan": "6fca757c20396dc2e604dcc61922264e9e3dc803"
            },
            {
              "version": "286a837217204b1ef105e3a554d0757e4fdfaac1",
              "status": "affected",
              "versionType": "git",
              "lessThan": "10d12b9240ebf96c785f0e2e4228318cd5f3a3eb"
            },
            {
              "version": "286a837217204b1ef105e3a554d0757e4fdfaac1",
              "status": "affected",
              "versionType": "git",
              "lessThan": "51f4e090b9f87b40c21b6daadb5c06e6c0a07b67"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "3.2",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "3.2"
            },
            {
              "version": "5.10.253",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "version": "5.15.203",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "version": "6.1.169",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "version": "6.6.135",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.82",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.18.23",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "version": "6.19.13",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.19.*"
            },
            {
              "version": "7.0",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}