CVE-2026-72021
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: ipvs: use parsed transport offset in SCTP state lookup set_sctp_state() reads the SCTP chunk header again in order to drive the IPVS SCTP state table. For IPv6 it computes the offset with sizeof(struct ipv6hdr), while the surrounding IPVS code uses iph.len from ip_vs_fill_iph_skb(), where ipv6_find_hdr() has already skipped extension headers and found the real transport header. This makes the state machine read from the wrong offset for IPv6 SCTP packets that carry extension headers. For example, an INIT packet with an 8-byte destination options header can be scheduled correctly by sctp_conn_schedule(), but set_sctp_state() reads the first byte of the SCTP verification tag as a DATA chunk type. The connection then moves from NONE to ESTABLISHED instead of INIT1, gets the longer established timeout, and updates the active/inactive destination counters incorrectly. This happens even though the SCTP handshake has not completed. Use the parsed transport offset passed down from ip_vs_set_state() for the SCTP chunk-header lookup. For IPv4 and IPv6 packets without extension headers this preserves the existing offset.
Severity
HIGH
CVSS score
8.2
(v3.1)
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-08-15 06:21:01.053000
Last modified
2026-10-19 22:17:22.433000
View original CVE JSON
{
"id": "CVE-2026-72021",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-08-15T06:21:01.053",
"lastModified": "2026-10-19T22:17:22.433",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: use parsed transport offset in SCTP state lookup\n\nset_sctp_state() reads the SCTP chunk header again in order to drive the\nIPVS SCTP state table. For IPv6 it computes the offset with\nsizeof(struct ipv6hdr), while the surrounding IPVS code uses iph.len from\nip_vs_fill_iph_skb(), where ipv6_find_hdr() has already skipped\nextension headers and found the real transport header.\n\nThis makes the state machine read from the wrong offset for IPv6 SCTP\npackets that carry extension headers. For example, an INIT packet with an\n8-byte destination options header can be scheduled correctly by\nsctp_conn_schedule(), but set_sctp_state() reads the first byte of the\nSCTP verification tag as a DATA chunk type. The connection then moves\nfrom NONE to ESTABLISHED instead of INIT1, gets the longer established\ntimeout, and updates the active/inactive destination counters\nincorrectly. This happens even though the SCTP handshake has not\ncompleted.\n\nUse the parsed transport offset passed down from ip_vs_set_state() for\nthe SCTP chunk-header lookup. For IPv4 and IPv6 packets without\nextension headers this preserves the existing offset."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"net/netfilter/ipvs/ip_vs_proto_sctp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
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"versionType": "git",
"status": "affected"
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},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"net/netfilter/ipvs/ip_vs_proto_sctp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "2.6.34",
"status": "affected"
},
{
"version": "0",
"lessThan": "2.6.34",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.10.261",
"lessThanOrEqual": "5.10.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.15.212",
"lessThanOrEqual": "5.15.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.178",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.145",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.97",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.40",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.1.5",
"lessThanOrEqual": "7.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"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:N/I:L/A:H",
"baseScore": 8.2,
"baseSeverity": "HIGH",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 3.9,
"impactScore": 4.2
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-10-16T15:50:11.842623Z",
"id": "CVE-2026-72021",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-20"
}
]
}
],
"references": [
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}