CVE-2026-99284 (GCVE-0-2026-99284)

Vulnerability from cvelistv5 – Published: 2026-11-07 20:40 – Updated: 2026-11-10 18:15
VLAI
Title
net: skbuff: propagate shared-frag marker in skb_zerocopy()
Summary
In the Linux kernel, the following vulnerability has been resolved: net: skbuff: propagate shared-frag marker in skb_zerocopy() skb_zerocopy() moves frag descriptors from @from into @to and takes a reference on each frag, but it does not copy skb_shinfo(from)->flags into skb_shinfo(to)->flags. A destination skb holding the same page-cache backed frags as the source therefore reports skb_has_shared_frag() as false. That breaks the invariant relied on by later in-place writers. ESP input checks skb_has_shared_frag() before deciding whether an uncloned nonlinear skb can skip skb_cow_data(); with the marker lost, an skb that skb_zerocopy() built for nfnetlink_queue or for an openvswitch upcall is decrypted in place, letting an unprivileged user write into the page cache of a root-owned read-only file. Propagate SKBFL_SHARED_FRAG when frag descriptors are copied, as done for the other frag-transfer helpers.
Severity
No CVSS data available.
Assigner
Linux CNA
References
Impacted products
Vendor Product Version
Linux Linux Affected: af2806f8f90a150160be898cd85332459c83c5cb , < fe8477e23dd2ee6bce231d65f2586a333b211dc0 (git)
Affected: af2806f8f90a150160be898cd85332459c83c5cb , < 1c623e3cbf43f12dd4a72712079bfa247a9b8ba3 (git)
Affected: af2806f8f90a150160be898cd85332459c83c5cb , < d7d6ff98d5d1b400f02211f962ac32cc0020aeab (git)
Affected: af2806f8f90a150160be898cd85332459c83c5cb , < 1a9c180cd8435917b7516edfb1c9148032c28773 (git)
Affected: af2806f8f90a150160be898cd85332459c83c5cb , < 79dc34beb1fdb3da79753e51e15c68591a2561fe (git)
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Linux Linux Affected: 3.14
Unaffected: 0 , < 3.14 (semver)
Unaffected: 6.12.117 , ≤ 6.12.* (semver)
Unaffected: 6.18.61 , ≤ 6.18.* (semver)
Unaffected: 7.2.15 , ≤ 7.2.* (semver)
Unaffected: 7.3.2 , ≤ 7.3.* (semver)
Unaffected: 7.4-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/skbuff.c"
          ],
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          "vendor": "Linux",
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              "versionType": "git"
            }
          ]
        },
        {
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          "product": "Linux",
          "programFiles": [
            "net/core/skbuff.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.14"
            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.117",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.61",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.15",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.3.*",
              "status": "unaffected",
              "version": "7.3.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.4-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.117",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.61",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                },
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                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: skbuff: propagate shared-frag marker in skb_zerocopy()\n\nskb_zerocopy() moves frag descriptors from @from into @to and takes a\nreference on each frag, but it does not copy skb_shinfo(from)-\u003eflags into\nskb_shinfo(to)-\u003eflags.  A destination skb holding the same page-cache\nbacked frags as the source therefore reports skb_has_shared_frag() as\nfalse.\n\nThat breaks the invariant relied on by later in-place writers.  ESP input\nchecks skb_has_shared_frag() before deciding whether an uncloned\nnonlinear skb can skip skb_cow_data(); with the marker lost, an skb that\nskb_zerocopy() built for nfnetlink_queue or for an openvswitch upcall is\ndecrypted in place, letting an unprivileged user write into the page\ncache of a root-owned read-only file.\n\nPropagate SKBFL_SHARED_FRAG when frag descriptors are copied, as done for\nthe other frag-transfer helpers."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-10T18:15:30.724Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/fe8477e23dd2ee6bce231d65f2586a333b211dc0"
        },
        {
          "url": "https://git.kernel.org/stable/c/1c623e3cbf43f12dd4a72712079bfa247a9b8ba3"
        },
        {
          "url": "https://git.kernel.org/stable/c/d7d6ff98d5d1b400f02211f962ac32cc0020aeab"
        },
        {
          "url": "https://git.kernel.org/stable/c/1a9c180cd8435917b7516edfb1c9148032c28773"
        },
        {
          "url": "https://git.kernel.org/stable/c/79dc34beb1fdb3da79753e51e15c68591a2561fe"
        }
      ],
      "title": "net: skbuff: propagate shared-frag marker in skb_zerocopy()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-99284",
    "datePublished": "2026-11-07T20:40:33.661Z",
    "dateReserved": "2026-09-25T10:25:14.405Z",
    "dateUpdated": "2026-11-10T18:15:30.724Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}



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