CVE-2026-74597 (GCVE-0-2026-74597)
Vulnerability from cvelistv5 – Published: 2026-08-22 15:31 – Updated: 2026-08-25 05:40
VLAI
EPSS
VEX
Title
ip6_tunnel: clear skb2->cb[] in ip6ip6_err()
Summary
In the Linux kernel, the following vulnerability has been resolved:
ip6_tunnel: clear skb2->cb[] in ip6ip6_err()
ip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the
quoted inner IPv6 packet, and then passes the clone to icmpv6_send().
The clone still carries the outer packet's inet6_skb_parm in skb->cb.
If the outer packet had a Home Address Option, IP6CB(skb2)->dsthao
remains non-zero after skb_pull(). icmpv6_send() later calls
mip6_addr_swap(), which uses that stale dsthao offset against the quoted
inner packet. A malformed inner destination-options header can then make
the HAO lookup and address swap run past the end of the quoted packet
and corrupt skb_shared_info.
Clear skb2->cb[] before pulling the quoted inner IPv6 packet so the
reply path does not reuse metadata left by the outer IPv6 stack.
Severity
9.8 (Critical)
Assigner
References
8 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
e490d1d85cf5e191791979e5f260d32eb4f703a8 , < 44fe898df302e91c5ee5acbc71ffa74e78e6c183
(git)
Affected: e490d1d85cf5e191791979e5f260d32eb4f703a8 , < 0dadb0620ab65949a8bc2439dd28ea3c942fe87d (git) Affected: e490d1d85cf5e191791979e5f260d32eb4f703a8 , < b6816536a2990c0db44a26130a03e40b441e829b (git) Affected: e490d1d85cf5e191791979e5f260d32eb4f703a8 , < 64e41736a26f37ab6215bc2e6df125df05aceb08 (git) Affected: e490d1d85cf5e191791979e5f260d32eb4f703a8 , < 484134e1eb07d700a73b1e4bbf3fb503e299be60 (git) Affected: e490d1d85cf5e191791979e5f260d32eb4f703a8 , < 4eb15c465337b18f44716c499cd6ad63eee0ad54 (git) Affected: e490d1d85cf5e191791979e5f260d32eb4f703a8 , < fbf40faa0414b753212494ad197542002e66ed9e (git) Affected: e490d1d85cf5e191791979e5f260d32eb4f703a8 , < f803c086399da277b5d0ff36a107d0f162751800 (git) |
guessed | |
| Linux | Linux |
Affected:
2.6.22
Unaffected: 0 , < 2.6.22 (semver) Unaffected: 5.10.265 , ≤ 5.10.* (semver) Unaffected: 5.15.216 , ≤ 5.15.* (semver) Unaffected: 6.1.183 , ≤ 6.1.* (semver) Unaffected: 6.6.152 , ≤ 6.6.* (semver) Unaffected: 6.12.104 , ≤ 6.12.* (semver) Unaffected: 6.18.45 , ≤ 6.18.* (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/ipv6/ip6_tunnel.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"version": "e490d1d85cf5e191791979e5f260d32eb4f703a8",
"versionType": "git"
},
{
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"status": "affected",
"version": "e490d1d85cf5e191791979e5f260d32eb4f703a8",
"versionType": "git"
},
{
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"status": "affected",
"version": "e490d1d85cf5e191791979e5f260d32eb4f703a8",
"versionType": "git"
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"versionType": "git"
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{
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{
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"status": "affected",
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"versionType": "git"
},
{
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"status": "affected",
"version": "e490d1d85cf5e191791979e5f260d32eb4f703a8",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/ipv6/ip6_tunnel.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.22"
},
{
"lessThan": "2.6.22",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.265",
"versionStartIncluding": "2.6.22",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.216",
"versionStartIncluding": "2.6.22",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.183",
"versionStartIncluding": "2.6.22",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.152",
"versionStartIncluding": "2.6.22",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.104",
"versionStartIncluding": "2.6.22",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.45",
"versionStartIncluding": "2.6.22",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.9",
"versionStartIncluding": "2.6.22",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "2.6.22",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nip6_tunnel: clear skb2-\u003ecb[] in ip6ip6_err()\n\nip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the\nquoted inner IPv6 packet, and then passes the clone to icmpv6_send().\nThe clone still carries the outer packet\u0027s inet6_skb_parm in skb-\u003ecb.\n\nIf the outer packet had a Home Address Option, IP6CB(skb2)-\u003edsthao\nremains non-zero after skb_pull(). icmpv6_send() later calls\nmip6_addr_swap(), which uses that stale dsthao offset against the quoted\ninner packet. A malformed inner destination-options header can then make\nthe HAO lookup and address swap run past the end of the quoted packet\nand corrupt skb_shared_info.\n\nClear skb2-\u003ecb[] before pulling the quoted inner IPv6 packet so the\nreply path does not reuse metadata left by the outer IPv6 stack."
}
],
"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 bug is reached when a remote peer sends a forged ICMPv6 error whose quoted payload is an IPv6-in-IPv6 tunnel datagram; processing follows the normal IPv6 receive path (ipv6_rcv -\u003e icmpv6_notify -\u003e tunnel6_err -\u003e ip6ip6_err) with no local access required.\nAC:L - The attacker controls the carrier IPv6 Home Address Option, quoted tunnel/inner headers, and ICMP error type; once an ip6tnl endpoint exists (normal for this subsystem), triggering the stale-dsthao path is reliable and needs no races or victim interaction.\nPR:N - No authentication or capabilities are required on the target; unprivileged remote senders can deliver crafted ICMPv6 errors that the kernel processes on the standard pre-auth receive path (INET6_PROTO_NOPOLICY).\nUI:N - Exploitation requires only delivering a malicious network packet; no victim must open files, click links, or perform any other action.\nS:U - Impact is in-kernel memory corruption on the receiving host within the same security authority; it does not by itself cross VM, container, or IOMMU boundaries.\nC:H - With CONFIG_IPV6_MIP6, mip6_addr_swap() uses the stale dsthao offset to scan the quoted inner packet and can read attacker-controlled bytes past the skb tail while resolving a fake HAO TLV before swapping addresses.\nI:H - The resulting 16-byte swap(iph-\u003esaddr, hao-\u003eaddr) can write beyond the quoted packet into skb_shared_info, giving attacker-influenced heap corruption suitable for further control-flow or data manipulation.\nA:H - Corrupting skb_shared_info from the network input path can cause kernel oops/panic or otherwise deny service on IPv6 tunnel endpoints, and the condition is repeatable with crafted packets."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-25T05:40:23.709Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/44fe898df302e91c5ee5acbc71ffa74e78e6c183"
},
{
"url": "https://git.kernel.org/stable/c/0dadb0620ab65949a8bc2439dd28ea3c942fe87d"
},
{
"url": "https://git.kernel.org/stable/c/b6816536a2990c0db44a26130a03e40b441e829b"
},
{
"url": "https://git.kernel.org/stable/c/64e41736a26f37ab6215bc2e6df125df05aceb08"
},
{
"url": "https://git.kernel.org/stable/c/484134e1eb07d700a73b1e4bbf3fb503e299be60"
},
{
"url": "https://git.kernel.org/stable/c/4eb15c465337b18f44716c499cd6ad63eee0ad54"
},
{
"url": "https://git.kernel.org/stable/c/fbf40faa0414b753212494ad197542002e66ed9e"
},
{
"url": "https://git.kernel.org/stable/c/f803c086399da277b5d0ff36a107d0f162751800"
}
],
"title": "ip6_tunnel: clear skb2-\u003ecb[] in ip6ip6_err()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74597",
"datePublished": "2026-08-22T15:31:47.120Z",
"dateReserved": "2026-08-15T05:44:03.919Z",
"dateUpdated": "2026-08-25T05:40:23.709Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-74597",
"date": "2026-10-13",
"epss": "0.00543",
"percentile": "0.44062"
},
"microsoft_vex": {
"current_release_date": "2026-09-25T02:24:59.000Z",
"cve": "CVE-2026-74597",
"id": "msrc_CVE-2026-74597",
"initial_release_date": "2026-08-24T01:01:37.000Z",
"product_status:fixed": "1",
"product_status:known_affected": "1",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "ip6_tunnel: clear skb2-\u003ecb[] in ip6ip6_err()",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74597.json",
"version": "4"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/ipv6/ip6_tunnel.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "44fe898df302e91c5ee5acbc71ffa74e78e6c183",
"status": "affected",
"version": "e490d1d85cf5e191791979e5f260d32eb4f703a8",
"versionType": "git"
},
{
"lessThan": "0dadb0620ab65949a8bc2439dd28ea3c942fe87d",
"status": "affected",
"version": "e490d1d85cf5e191791979e5f260d32eb4f703a8",
"versionType": "git"
},
{
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"status": "affected",
"version": "e490d1d85cf5e191791979e5f260d32eb4f703a8",
"versionType": "git"
},
{
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"status": "affected",
"version": "e490d1d85cf5e191791979e5f260d32eb4f703a8",
"versionType": "git"
},
{
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"status": "affected",
"version": "e490d1d85cf5e191791979e5f260d32eb4f703a8",
"versionType": "git"
},
{
"lessThan": "4eb15c465337b18f44716c499cd6ad63eee0ad54",
"status": "affected",
"version": "e490d1d85cf5e191791979e5f260d32eb4f703a8",
"versionType": "git"
},
{
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"status": "affected",
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"versionType": "git"
},
{
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"status": "affected",
"version": "e490d1d85cf5e191791979e5f260d32eb4f703a8",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/ipv6/ip6_tunnel.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.22"
},
{
"lessThan": "2.6.22",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nip6_tunnel: clear skb2-\u003ecb[] in ip6ip6_err()\n\nip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the\nquoted inner IPv6 packet, and then passes the clone to icmpv6_send().\nThe clone still carries the outer packet\u0027s inet6_skb_parm in skb-\u003ecb.\n\nIf the outer packet had a Home Address Option, IP6CB(skb2)-\u003edsthao\nremains non-zero after skb_pull(). icmpv6_send() later calls\nmip6_addr_swap(), which uses that stale dsthao offset against the quoted\ninner packet. A malformed inner destination-options header can then make\nthe HAO lookup and address swap run past the end of the quoted packet\nand corrupt skb_shared_info.\n\nClear skb2-\u003ecb[] before pulling the quoted inner IPv6 packet so the\nreply path does not reuse metadata left by the outer IPv6 stack."
}
],
"id": "CVE-2026-74597",
"lastModified": "2026-08-25T06:18:35.440",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-22T16:16:32.040",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0dadb0620ab65949a8bc2439dd28ea3c942fe87d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/44fe898df302e91c5ee5acbc71ffa74e78e6c183"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/484134e1eb07d700a73b1e4bbf3fb503e299be60"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4eb15c465337b18f44716c499cd6ad63eee0ad54"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/64e41736a26f37ab6215bc2e6df125df05aceb08"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b6816536a2990c0db44a26130a03e40b441e829b"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f803c086399da277b5d0ff36a107d0f162751800"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/fbf40faa0414b753212494ad197542002e66ed9e"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Important",
"current_release_date": "2026-09-30T16:12:45+00:00",
"cve": "CVE-2026-74597",
"id": "CVE-2026-74597",
"initial_release_date": "2026-08-22T00:00:00+00:00",
"product_status:known_affected": "260",
"product_status:known_not_affected": "14",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: ip6_tunnel: clear skb2-\u003ecb[] in ip6ip6_err()",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74597.json",
"version": "3"
}
}
}
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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.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.