CVE-2026-53362

Status: AnalyzedHigh (7.8)⚠ Active exploitation

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

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.

Read full descriptionShow less

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.

Technical details traces, logs and code from the original report

	alloclen = fragheaderlen + transhdrlen;
	pagedlen = datalen - transhdrlen;

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Base score: 7.8

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.71%
Percentile among all scored CVEs: 52
Score date: 10/4/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

CISA KEV — actively exploited

Added to catalog: 8/27/2026
Remediation due date: 8/30/2026
Known ransomware use: Unknown

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Secondary impactT1499.004 Application or System Exploitationimpact65 %

Buffer overflow (CWE-787) en kernel Linux activable por usuario sin privilegios via UDPv6 socket permite ejecución de código o DoS; vector AV:L/PR:L y KEV activa sustentan escalada/explotación local.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Threat Intelligence Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Affected technologies (1)

Linux — Linux Kernel

CWEs

CWE-787
CWE-122

References

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-53362",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-53362",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "active"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-08-28T03:55:26.491246Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "lessThan": "14200d435af9a9eeb444f529fc2f689a236b7962",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "lessThan": "65fb14cbebb0cd0eff903a22d33537ddc8b95769",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "lessThan": "46f201f8b4c39633a1fa3dc12459f506d470993d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "lessThan": "6374fb9edf72c67a118a2c214a0dddd04c921e0a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "lessThan": "e9eacf19281ea2498b36291b56c9606118c2d74e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "773ba4fe9104a64a54d1c00f0fb6ffb95def2b03",
              "lessThan": "736b380e28d0480c7bc3e022f1950f31fe53a7c5",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/ipv6/ip6_output.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.1.177",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.144",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.95",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.38",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.3",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/ipv6/ip6_output.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-07-04T12:17:02.113",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/14200d435af9a9eeb444f529fc2f689a236b7962",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/46f201f8b4c39633a1fa3dc12459f506d470993d",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6374fb9edf72c67a118a2c214a0dddd04c921e0a",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/65fb14cbebb0cd0eff903a22d33537ddc8b95769",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/736b380e28d0480c7bc3e022f1950f31fe53a7c5",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e9eacf19281ea2498b36291b56c9606118c2d74e",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-53362",
      "tags": [
        "US Government Resource"
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ]
    },
    {
      "type": "Secondary",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
        {
          "lang": "en",
          "value": "CWE-122"
        }
      ]
    }
  ],
  "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's 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->end 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()'s 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."
    }
  ],
  "lastModified": "2026-08-28T20:18:10.133",
  "cisaActionDue": "2026-08-30",
  "cisaExploitAdd": "2026-08-27",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E1C3142A-8469-4087-A10A-726FF6961047",
              "versionEndExcluding": "6.1.177",
              "versionStartIncluding": "6.0"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "C8AD3BC8-C843-423C-B9DB-CB52F67F578E",
              "versionEndExcluding": "6.6.144",
              "versionStartIncluding": "6.2"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "4E206B86-E0E3-4394-A93F-39F2D50A8AA8",
              "versionEndExcluding": "6.12.95",
              "versionStartIncluding": "6.7"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "FA591B28-5D62-449E-BDBE-3C9391BF070A",
              "versionEndExcluding": "6.18.38",
              "versionStartIncluding": "6.13"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "9526B150-E2B3-4C6F-8AE5-1AF92B75AD9E",
              "versionEndExcluding": "7.1.3",
              "versionStartIncluding": "6.19"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "cisaRequiredAction": "Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.",
  "cisaVulnerabilityName": "Linux Kernel Unspecified Vulnerability"
}