CVE-2026-64566 (GCVE-0-2026-64566)

Vulnerability from cvelistv5 – Published: 2026-08-05 08:06 – Updated: 2026-08-08 15:13
VLAI
Title
xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()
Summary
In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags() When iptfs_skb_add_frags() copies frag references from the source frag walk into a new SKB, it increments the page reference count via __skb_frag_ref() but does not propagate SKBFL_SHARED_FRAG to the destination SKB's skb_shinfo->flags. If the source SKB carries shared frags (e.g. from a page-pool backed receive path), the new inner SKB will appear to ESP as having privately owned frags. A subsequent esp_input() call for a nested transport-mode SA then takes the no-COW fast path and decrypts in place, writing over pages that are still referenced by the outer IPTFS SKB. This causes kernel-visible memory corruption and can trigger a panic. All other frag-transfer helpers in the kernel (skb_try_coalesce, skb_gro_receive, __pskb_copy_fclone, skb_shift, skb_segment) correctly propagate SKBFL_SHARED_FRAG; align iptfs_skb_add_frags() with this convention by setting the flag inside the loop immediately after __skb_frag_ref() and nr_frags++, so every exit path that attaches a frag unconditionally propagates SKBFL_SHARED_FRAG.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7 , < d8aaf06b29f5a0b6186cf68d21c7d63678ee3891 (git)
Affected: 5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7 , < ffd64e0717efd83fbf3396ab4e5ac6d795dac4d0 (git)
Affected: 5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7 , < 430ea57d6daf765e88f90046afbfd1e071cb7200 (git)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2-rc4 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/xfrm/xfrm_iptfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
            },
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          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "6.14"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "versionType": "semver"
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              "version": "7.1.6",
              "versionType": "semver"
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              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
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                  "vulnerable": true
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                  "vulnerable": true
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              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()\n\nWhen iptfs_skb_add_frags() copies frag references from the source\nfrag walk into a new SKB, it increments the page reference count via\n__skb_frag_ref() but does not propagate SKBFL_SHARED_FRAG to the\ndestination SKB\u0027s skb_shinfo-\u003eflags.\n\nIf the source SKB carries shared frags (e.g. from a page-pool backed\nreceive path), the new inner SKB will appear to ESP as having privately\nowned frags.  A subsequent esp_input() call for a nested transport-mode\nSA then takes the no-COW fast path and decrypts in place, writing over\npages that are still referenced by the outer IPTFS SKB.  This causes\nkernel-visible memory corruption and can trigger a panic.\n\nAll other frag-transfer helpers in the kernel (skb_try_coalesce,\nskb_gro_receive, __pskb_copy_fclone, skb_shift, skb_segment) correctly\npropagate SKBFL_SHARED_FRAG; align iptfs_skb_add_frags() with this\nconvention by setting the flag inside the loop immediately after\n__skb_frag_ref() and nr_frags++, so every exit path that attaches a frag\nunconditionally propagates SKBFL_SHARED_FRAG."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The flaw is on the IPsec IPTFS receive path: inbound ESP packets hit xfrm_input \u2192 iptfs_input \u2192 iptfs_skb_add_frags, then reinjected inner packets reach nested transport-mode esp_input(); a remote IPTFS/IPsec peer triggers it with network packets.\nAC:L - On a host with IPTFS plus a nested transport-mode SA, the peer fully controls packet sizes and ESP payloads that take the frag-share path and drive in-place decrypt; no race or attacker-uncontrollable memory layout is required.\nPR:N - Exploitation is by a remote IPsec peer sending packets to an already-configured IPTFS endpoint; no local account or capability on the target is required, and SA presence is a deployment precondition rather than an attacker privilege.\nUI:N - Packets are processed in softirq/NAPI receive context with no victim action such as mounting, opening a file, or otherwise interacting with the system.\nS:U - Corruption is of shared skb/NIC fragment pages within the same kernel security authority; this is not a VM escape, IOMMU bypass, or cross-sandbox boundary crossing.\nC:H - Missing SKBFL_SHARED_FRAG lets nested esp_input() overwrite pages still referenced by the outer IPTFS skb and sibling inners, yielding attacker-influenced memory corruption that can be leveraged for information disclosure.\nI:H - In-place ESP decryption writes attacker-controlled plaintext into pages still held by other skbs, providing a memory-corruption write primitive capable of integrity compromise and control-flow impact.\nA:H - The same shared-page overwrite causes kernel-visible memory corruption and can panic/oops the host, fully denying availability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-08T15:13:07.286Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d8aaf06b29f5a0b6186cf68d21c7d63678ee3891"
        },
        {
          "url": "https://git.kernel.org/stable/c/ffd64e0717efd83fbf3396ab4e5ac6d795dac4d0"
        },
        {
          "url": "https://git.kernel.org/stable/c/430ea57d6daf765e88f90046afbfd1e071cb7200"
        }
      ],
      "title": "xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64566",
    "datePublished": "2026-08-05T08:06:18.645Z",
    "dateReserved": "2026-07-19T15:36:31.797Z",
    "dateUpdated": "2026-08-08T15:13:07.286Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-08-10",
      "epss": "0.00352",
      "percentile": "0.27879"
    },
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    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-08-06T10:29:04+00:00",
      "cve": "CVE-2026-64566",
      "id": "CVE-2026-64566",
      "initial_release_date": "2026-08-05T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64566.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-06T23:56:36Z",
      "cve": "CVE-2026-64566",
      "id": "CVE-2026-64566",
      "initial_release_date": "2026-08-06T01:06:33Z",
      "product_status:known_not_affected": "296",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64566",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64566.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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