FKIE_CVE-2026-53362

Vulnerability from fkie_nvd - Published: 2026-07-04 12:17 - Updated: 2026-07-04 12:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/14200d435af9a9eeb444f529fc2f689a236b7962
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/46f201f8b4c39633a1fa3dc12459f506d470993d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6374fb9edf72c67a118a2c214a0dddd04c921e0a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/65fb14cbebb0cd0eff903a22d33537ddc8b95769
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/736b380e28d0480c7bc3e022f1950f31fe53a7c5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e9eacf19281ea2498b36291b56c9606118c2d74e
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/ip6_output.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "14200d435af9a9eeb444f529fc2f689a236b7962",
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "versionType": "git"
            },
            {
              "lessThan": "65fb14cbebb0cd0eff903a22d33537ddc8b95769",
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "versionType": "git"
            },
            {
              "lessThan": "46f201f8b4c39633a1fa3dc12459f506d470993d",
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "versionType": "git"
            },
            {
              "lessThan": "6374fb9edf72c67a118a2c214a0dddd04c921e0a",
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "versionType": "git"
            },
            {
              "lessThan": "e9eacf19281ea2498b36291b56c9606118c2d74e",
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "versionType": "git"
            },
            {
              "lessThan": "736b380e28d0480c7bc3e022f1950f31fe53a7c5",
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/ip6_output.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.177",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.144",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.95",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.38",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "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\nipv6: account for fraggap on the paged allocation path\n\nIn __ip6_append_data(), when the paged-allocation branch is taken\n(MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are\ncomputed as\n\n\talloclen = fragheaderlen + transhdrlen;\n\tpagedlen = datalen - transhdrlen;\n\ndatalen already includes fraggap (datalen = length + fraggap). When\nfraggap is non-zero, this is not the first skb and transhdrlen is zero.\nThe fraggap bytes carried over from the previous skb are copied just past\nthe fragment headers in the new skb\u0027s linear area. The linear area is\ntherefore undersized by fraggap bytes while pagedlen is overstated by the\nsame amount, and the copy writes past skb-\u003eend into the trailing\nskb_shared_info.\n\nAn unprivileged user can trigger this via a UDPv6 socket using\nMSG_MORE together with MSG_SPLICE_PAGES.\n\nThe bad accounting was introduced by commit 773ba4fe9104 (\"ipv6:\navoid partial copy for zc\"). Before commit ce650a166335 (\"udp6: Fix\n__ip6_append_data()\u0027s handling of MSG_SPLICE_PAGES\"), the negative\ncopy value caused -EINVAL to be returned. That later commit allowed\nMSG_SPLICE_PAGES to proceed in this case, making the corruption\ntriggerable.\n\nThe non-paged branch sets alloclen to fraglen, which already accounts\nfor fraggap because datalen does. Bring the paged branch in line by\nadding fraggap to alloclen and subtracting it from pagedlen.\n\nAfter this adjustment, copy no longer collapses to -fraggap on the\npaged path, so remove the stale comment describing that old arithmetic.\nSince a negative copy is no longer expected for a valid MSG_SPLICE_PAGES\ncase, remove the MSG_SPLICE_PAGES exception from the negative copy check."
    }
  ],
  "id": "CVE-2026-53362",
  "lastModified": "2026-07-04T12:17:02.113",
  "metrics": {},
  "published": "2026-07-04T12:17:02.113",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/14200d435af9a9eeb444f529fc2f689a236b7962"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/46f201f8b4c39633a1fa3dc12459f506d470993d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6374fb9edf72c67a118a2c214a0dddd04c921e0a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/65fb14cbebb0cd0eff903a22d33537ddc8b95769"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/736b380e28d0480c7bc3e022f1950f31fe53a7c5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e9eacf19281ea2498b36291b56c9606118c2d74e"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}


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