CVE-2026-99284

Full vulnerability record from the local CVENow database.

Description

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

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-11-07 21:17:00.603000

Last modified

2026-11-07 21:17:00.603000

View original CVE JSON

{
  "id": "CVE-2026-99284",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-11-07T21:17:00.603",
  "lastModified": "2026-11-07T21:17:00.603",
  "vulnStatus": "Received",
  "cveTags": [],
  "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)->flags into\nskb_shinfo(to)->flags.  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."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "net/core/skbuff.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "af2806f8f90a150160be898cd85332459c83c5cb",
              "lessThan": "1c623e3cbf43f12dd4a72712079bfa247a9b8ba3",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "af2806f8f90a150160be898cd85332459c83c5cb",
              "lessThan": "d7d6ff98d5d1b400f02211f962ac32cc0020aeab",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "af2806f8f90a150160be898cd85332459c83c5cb",
              "lessThan": "1a9c180cd8435917b7516edfb1c9148032c28773",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "af2806f8f90a150160be898cd85332459c83c5cb",
              "lessThan": "79dc34beb1fdb3da79753e51e15c68591a2561fe",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "net/core/skbuff.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "3.14",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "3.14",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.61",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.15",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3.2",
              "lessThanOrEqual": "7.3.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.4-rc1",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1a9c180cd8435917b7516edfb1c9148032c28773",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1c623e3cbf43f12dd4a72712079bfa247a9b8ba3",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/79dc34beb1fdb3da79753e51e15c68591a2561fe",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d7d6ff98d5d1b400f02211f962ac32cc0020aeab",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}