CVE-2026-43186 (GCVE-0-2026-43186)
Vulnerability from cvelistv5 – Published: 2026-05-06 11:27 – Updated: 2026-05-08 12:41
VLAI?
Title
ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()
Summary
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).
Severity ?
9.8 (Critical)
Assigner
References
Impacted products
| Vendor | Product | Version | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux |
Affected:
9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 , < f4d9d4b8fd839719d564651671e24c62c545c23b
(git)
Affected: 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 , < fb3c662fafebc5b9d74417ed1de8759f6bb72143 (git) Affected: 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 , < 632d233cf2e64a46865ae2c064ae3c9df7c8864f (git) Affected: 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 , < 0591d6509c2ff13f09ea2998434aba0c0472e978 (git) Affected: 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 , < e90346a2f1e8917d5760a44a1f61c44e3b36d96b (git) Affected: 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 , < ea3632aefc04205436868541638e26f4a74d5637 (git) Affected: 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 , < 6db8b56eed62baacaf37486e83378a72635c04cc (git) |
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{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"include/net/ioam6.h",
"net/ipv6/exthdrs.c",
"net/ipv6/ioam6.c",
"net/ipv6/ioam6_iptunnel.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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{
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{
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{
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"product": "Linux",
"programFiles": [
"include/net/ioam6.h",
"net/ipv6/exthdrs.c",
"net/ipv6/ioam6.c",
"net/ipv6/ioam6_iptunnel.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.15"
},
{
"lessThan": "5.15",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.202",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.165",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.128",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.75",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.16",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "5.15",
"vulnerable": true
},
{
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},
{
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},
{
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.19.6",
"versionStartIncluding": "5.15",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()\n\nOn the receive path, __ioam6_fill_trace_data() uses trace-\u003enodelen\nto decide how much data to write for each node. It trusts this field\nas-is from the incoming packet, with no consistency check against\ntrace-\u003etype (the 24-bit field that tells which data items are\npresent). A crafted packet can set nodelen=0 while setting type bits\n0-21, causing the function to write ~100 bytes past the allocated\nregion (into skb_shared_info), which corrupts adjacent heap memory\nand leads to a kernel panic.\n\nAdd a shared helper ioam6_trace_compute_nodelen() in ioam6.c to\nderive the expected nodelen from the type field, and use it:\n\n - in ioam6_iptunnel.c (send path, existing validation) to replace\n the open-coded computation;\n - in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose\n nodelen is inconsistent with the type field, before any data is\n written.\n\nPer RFC 9197, bits 12-21 are each short (4-octet) fields, so they\nare included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to\n0xff1ffc00)."
}
],
"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"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-05-08T12:41:04.575Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/f4d9d4b8fd839719d564651671e24c62c545c23b"
},
{
"url": "https://git.kernel.org/stable/c/fb3c662fafebc5b9d74417ed1de8759f6bb72143"
},
{
"url": "https://git.kernel.org/stable/c/632d233cf2e64a46865ae2c064ae3c9df7c8864f"
},
{
"url": "https://git.kernel.org/stable/c/0591d6509c2ff13f09ea2998434aba0c0472e978"
},
{
"url": "https://git.kernel.org/stable/c/e90346a2f1e8917d5760a44a1f61c44e3b36d96b"
},
{
"url": "https://git.kernel.org/stable/c/ea3632aefc04205436868541638e26f4a74d5637"
},
{
"url": "https://git.kernel.org/stable/c/6db8b56eed62baacaf37486e83378a72635c04cc"
}
],
"title": "ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()",
"x_generator": {
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}
}
},
"cveMetadata": {
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"assignerShortName": "Linux",
"cveId": "CVE-2026-43186",
"datePublished": "2026-05-06T11:27:57.053Z",
"dateReserved": "2026-05-01T14:12:55.991Z",
"dateUpdated": "2026-05-08T12:41:04.575Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-43186",
"date": "2026-05-09",
"epss": "0.00138",
"percentile": "0.33274"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2026-43186\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-06T12:16:37.300\",\"lastModified\":\"2026-05-08T13:16:42.557\",\"vulnStatus\":\"Undergoing Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()\\n\\nOn the receive path, __ioam6_fill_trace_data() uses trace-\u003enodelen\\nto decide how much data to write for each node. It trusts this field\\nas-is from the incoming packet, with no consistency check against\\ntrace-\u003etype (the 24-bit field that tells which data items are\\npresent). A crafted packet can set nodelen=0 while setting type bits\\n0-21, causing the function to write ~100 bytes past the allocated\\nregion (into skb_shared_info), which corrupts adjacent heap memory\\nand leads to a kernel panic.\\n\\nAdd a shared helper ioam6_trace_compute_nodelen() in ioam6.c to\\nderive the expected nodelen from the type field, and use it:\\n\\n - in ioam6_iptunnel.c (send path, existing validation) to replace\\n the open-coded computation;\\n - in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose\\n nodelen is inconsistent with the type field, before any data is\\n written.\\n\\nPer RFC 9197, bits 12-21 are each short (4-octet) fields, so they\\nare included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to\\n0xff1ffc00).\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0591d6509c2ff13f09ea2998434aba0c0472e978\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/632d233cf2e64a46865ae2c064ae3c9df7c8864f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6db8b56eed62baacaf37486e83378a72635c04cc\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e90346a2f1e8917d5760a44a1f61c44e3b36d96b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ea3632aefc04205436868541638e26f4a74d5637\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f4d9d4b8fd839719d564651671e24c62c545c23b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fb3c662fafebc5b9d74417ed1de8759f6bb72143\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
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
| Author | Source | Type | Date | Other |
|---|
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.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- 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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