FKIE_CVE-2026-97612
Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 15:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: mpls: clear inner_protocol when the last label is popped
skb_mpls_push() records the pre-encapsulation network header once, gated
on !skb->inner_protocol. skb_mpls_pop() never clears that record, so it
outlives the encapsulation it describes.
Open vSwitch can then re-push MPLS onto a packet whose
inner_network_header still points at the older, deeper offset: push a
label, pop every label, recirculate (ovs_flow_key_update() re-derives
key->eth.type and resets network_header, but leaves inner_*), then push
again. ovs_fragment() trusts the record:
skb->network_header = skb->inner_network_header;
so skb_network_offset() goes negative. The bound check is signed:
if (skb_network_offset(skb) > MAX_L2_LEN)
a negative offset passes it, and prepare_frag() widens the value:
unsigned int hlen = skb_network_offset(skb);
memcpy(&data->l2_data, skb->data, hlen);
which is a ~4GiB memcpy out of a 30-byte per-CPU buffer.
Reproduced on v7.3-rc1. RDX is the truncated length, (unsigned int)(-8):
BUG: unable to handle page fault for address: ffffe8ffffc16000
#PF: supervisor write access in kernel mode
Oops: 0002 [#1] SMP KASAN NOPTI
RIP: 0010:memcpy+0x8/0x20
RDX: 00000000fffffff8 RSI: ffff888105d732db RDI: ffffe8ffffc16000
prepare_frag+0x3df/0x4e0
ovs_fragment+0x589/0x7e0
do_output+0x4ce/0x5e0
do_execute_actions+0x55d2/0x7b30
ovs_execute_actions+0xea/0x450
Same root-cause shape as commit 975b5b067f52 ("ipv6: sr: restore network
header before routing and forwarding"): a stale network header offset
reaching a consumer that widens it. Here it originates in the MPLS
push/pop path.
Clear inner_protocol once the packet is no longer MPLS, so a later push
re-records the current header. net/sched/act_mpls.c is the only other
skb_mpls_pop() caller and gets the same fix; sch_frag.c saves and
restores inner_protocol around fragmentation in the same way OVS does.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/core/skbuff.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "011e17b5cae19b9f6a150923275e41c278de64f0",
"status": "affected",
"version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
"versionType": "git"
},
{
"lessThan": "da8c3a7f5d3137fec4ff60a6248f5f6d66b6a63e",
"status": "affected",
"version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
"versionType": "git"
},
{
"lessThan": "b39120523475d6b436be7f6cb27d48064148a327",
"status": "affected",
"version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
"versionType": "git"
},
{
"lessThan": "78a86d75a70e1e227711c72865c59b1422d0a5ae",
"status": "affected",
"version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/core/skbuff.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.9"
},
{
"lessThan": "4.9",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.53",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3-rc3",
"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\nnet: mpls: clear inner_protocol when the last label is popped\n\nskb_mpls_push() records the pre-encapsulation network header once, gated\non !skb-\u003einner_protocol. skb_mpls_pop() never clears that record, so it\noutlives the encapsulation it describes.\n\nOpen vSwitch can then re-push MPLS onto a packet whose\ninner_network_header still points at the older, deeper offset: push a\nlabel, pop every label, recirculate (ovs_flow_key_update() re-derives\nkey-\u003eeth.type and resets network_header, but leaves inner_*), then push\nagain. ovs_fragment() trusts the record:\n\n\tskb-\u003enetwork_header = skb-\u003einner_network_header;\n\nso skb_network_offset() goes negative. The bound check is signed:\n\n\tif (skb_network_offset(skb) \u003e MAX_L2_LEN)\n\na negative offset passes it, and prepare_frag() widens the value:\n\n\tunsigned int hlen = skb_network_offset(skb);\n\tmemcpy(\u0026data-\u003el2_data, skb-\u003edata, hlen);\n\nwhich is a ~4GiB memcpy out of a 30-byte per-CPU buffer.\n\nReproduced on v7.3-rc1. RDX is the truncated length, (unsigned int)(-8):\n\n BUG: unable to handle page fault for address: ffffe8ffffc16000\n #PF: supervisor write access in kernel mode\n Oops: 0002 [#1] SMP KASAN NOPTI\n RIP: 0010:memcpy+0x8/0x20\n RDX: 00000000fffffff8 RSI: ffff888105d732db RDI: ffffe8ffffc16000\n prepare_frag+0x3df/0x4e0\n ovs_fragment+0x589/0x7e0\n do_output+0x4ce/0x5e0\n do_execute_actions+0x55d2/0x7b30\n ovs_execute_actions+0xea/0x450\n\nSame root-cause shape as commit 975b5b067f52 (\"ipv6: sr: restore network\nheader before routing and forwarding\"): a stale network header offset\nreaching a consumer that widens it. Here it originates in the MPLS\npush/pop path.\n\nClear inner_protocol once the packet is no longer MPLS, so a later push\nre-records the current header. net/sched/act_mpls.c is the only other\nskb_mpls_pop() caller and gets the same fix; sch_frag.c saves and\nrestores inner_protocol around fragmentation in the same way OVS does."
}
],
"id": "CVE-2026-97612",
"lastModified": "2026-09-25T15:18:01.500",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-09-25T11:17:15.330",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/011e17b5cae19b9f6a150923275e41c278de64f0"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/78a86d75a70e1e227711c72865c59b1422d0a5ae"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b39120523475d6b436be7f6cb27d48064148a327"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/da8c3a7f5d3137fec4ff60a6248f5f6d66b6a63e"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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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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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
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