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ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data() On the receive path, __ioam6_fill_trace_data() uses trace->nodelen to decide how much data to write for each node. It trusts this field as-is from the incoming packet, with no consistency check against trace->type (the 24-bit field that tells which data items are present). A crafted packet can set nodelen=0 while setting type bits 0-21, causing the function to write ~100 bytes past the allocated region (into skb_shared_info), which corrupts adjacent heap memory and leads to a kernel panic. Add a shared helper ioam6_trace_compute_nodelen() in ioam6.c to derive the expected nodelen from the type field, and use it: - in ioam6_iptunnel.c (send path, existing validation) to replace the open-coded computation; - in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose nodelen is inconsistent with the type field, before any data is written. Per RFC 9197, bits 12-21 are each short (4-octet) fields, so they are included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to 0xff1ffc00).

Announced Source revision 1
Original source ↗

CVE-2026-43186

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-43186

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
        "lessThan": "f4d9d4b8fd839719d564651671e24c62c545c23b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
        "lessThan": "fb3c662fafebc5b9d74417ed1de8759f6bb72143",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
        "lessThan": "632d233cf2e64a46865ae2c064ae3c9df7c8864f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
        "lessThan": "0591d6509c2ff13f09ea2998434aba0c0472e978",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
        "lessThan": "e90346a2f1e8917d5760a44a1f61c44e3b36d96b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
        "lessThan": "ea3632aefc04205436868541638e26f4a74d5637",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
        "lessThan": "6db8b56eed62baacaf37486e83378a72635c04cc",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "include/net/ioam6.h",
      "net/ipv6/exthdrs.c",
      "net/ipv6/ioam6.c",
      "net/ipv6/ioam6_iptunnel.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.15"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.15",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.15.202",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.165",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.128",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.75",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.16",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "6.19.6",
        "versionType": "semver",
        "lessThanOrEqual": "6.19.*"
      },
      {
        "status": "unaffected",
        "version": "7.0",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "include/net/ioam6.h",
      "net/ipv6/exthdrs.c",
      "net/ipv6/ioam6.c",
      "net/ipv6/ioam6_iptunnel.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-43186

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#40039 · Revision 1
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Publisher date
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