CVE-2026-43341 (GCVE-0-2026-43341)
Vulnerability from cvelistv5
Published
2026-05-08 13:37
Modified
2026-08-05 12:27
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net/ipv6: ioam6: prevent schema length wraparound in trace fill ioam6_fill_trace_data() stores the schema contribution to the trace length in a u8. With bit 22 enabled and the largest schema payload, sclen becomes 1 + 1020 / 4, wraps from 256 to 0, and bypasses the remaining-space check. __ioam6_fill_trace_data() then positions the write cursor without reserving the schema area but still copies the 4-byte schema header and the full schema payload, overrunning the trace buffer. Keep sclen in an unsigned int so the remaining-space check and the write cursor calculation both see the full schema length.
References
Impacted products
Vendor Product Version
Linux Linux Version: 8c6f6fa6772696be0c047a711858084b38763728
Version: 8c6f6fa6772696be0c047a711858084b38763728
Version: 8c6f6fa6772696be0c047a711858084b38763728
Version: 8c6f6fa6772696be0c047a711858084b38763728
Version: 8c6f6fa6772696be0c047a711858084b38763728
Version: 8c6f6fa6772696be0c047a711858084b38763728
Version: 8c6f6fa6772696be0c047a711858084b38763728
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{
  "containers": {
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/ioam6.c"
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              "version": "6.19.12",
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            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "versionEndExcluding": "5.15.210",
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                  "vulnerable": true
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              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/ipv6: ioam6: prevent schema length wraparound in trace fill\n\nioam6_fill_trace_data() stores the schema contribution to the trace\nlength in a u8. With bit 22 enabled and the largest schema payload,\nsclen becomes 1 + 1020 / 4, wraps from 256 to 0, and bypasses the\nremaining-space check. __ioam6_fill_trace_data() then positions the\nwrite cursor without reserving the schema area but still copies the\n4-byte schema header and the full schema payload, overrunning the trace\nbuffer.\n\nKeep sclen in an unsigned int so the remaining-space check and the write\ncursor calculation both see the full schema length."
        }
      ],
      "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 - Inbound IPv6 Hop-by-Hop IOAM packets reach `ipv6_hop_ioam()` and then `ioam6_fill_trace_data()` on an IOAM-enabled interface. In a reasonable IOAM deployment with an active max-size schema, the triggering packet is network-delivered and unauthenticated.\nAC:L - There is no race or timing requirement; the attacker supplies a malformed IOAM trace with bit 22 set and insufficient remaining trace space. The required IOAM/schema configuration is part of the affected deployment scenario, and triggering is otherwise deterministic.\nPR:N - The inbound packet path does not require the sender to hold kernel privileges or authenticate. Although configuring IOAM namespaces/schemas requires administrative capability, a remote attacker can trigger the bug against an already configured IOAM node.\nUI:N - No victim user action is required after the affected IOAM node is configured. Packet receipt alone invokes the vulnerable trace fill path.\nS:U - The corruption occurs within the Linux kernel networking stack and impacts the same kernel security authority. This is not a guest-to-host, IOMMU, or other cross-scope boundary bypass.\nC:H - The bug is a heap/out-of-bounds write from the skb trace area caused by schema length wraparound. Kernel memory corruption can be leveraged to expose sensitive kernel memory or build stronger primitives.\nI:H - The vulnerable path copies the 4-byte schema header and up to 1020 bytes of schema data past the reserved trace buffer. This is a high-impact out-of-bounds write with potential for arbitrary kernel memory corruption/control-flow exploitation.\nA:H - The overflow can corrupt adjacent skb/kernel heap memory and is expected to cause kernel oops, panic, or networking instability. It can be triggered repeatedly with crafted packets in the affected deployment."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:27:21.749Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d3a1fb2ca323d7a4e10ab3afbfa25e6d8921e4f2"
        },
        {
          "url": "https://git.kernel.org/stable/c/e96d48b37708d53cbdc47f6f60b0714fc4a5f596"
        },
        {
          "url": "https://git.kernel.org/stable/c/d1b041080086e91d3733a5438a8c51ad5d3d8e09"
        },
        {
          "url": "https://git.kernel.org/stable/c/77695a69baca9b99d95fad09fc78c2318736604f"
        },
        {
          "url": "https://git.kernel.org/stable/c/184d2e9db27c0f76226b5cad16fe29510a5d2280"
        },
        {
          "url": "https://git.kernel.org/stable/c/d6e1c9b02d85a4f1f4ba6d68e916d9b610a3ed7d"
        },
        {
          "url": "https://git.kernel.org/stable/c/5e67ba9bb531e1ec6599a82a065dea9040b9ce50"
        }
      ],
      "title": "net/ipv6: ioam6: prevent schema length wraparound in trace fill",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43341",
    "datePublished": "2026-05-08T13:37:19.256Z",
    "dateReserved": "2026-05-01T14:12:56.003Z",
    "dateUpdated": "2026-08-05T12:27:21.749Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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