MOKSHA-2026-0077 (moksha-2026-0077)
Vulnerability from moksha – Published: 2026-04-24 06:00 – Updated:
VLAI?
Title
VIF NIC Offload Disablement via VIF.other_config ethtool Keys
Summary
A vm-admin in XAPI-based hypervisors (XenServer, XCP-ng) can disable NIC offload features (TSO, GSO, etc.) on VIF backend devices by setting ethtool-tso=off and similar keys in VIF.other_config. The VIF hotplug script (vif-real:85-97) executes ethtool -K to disable offloads. This forces host CPU to perform software segmentation, increasing CPU utilization and degrading performance for co-located VMs. VIF.other_config has zero map_keys_roles entries - all ethtool keys are writable by vm-admin.
Severity ?
4.3 (Medium)
CWE
- CWE-862 - Missing Authorization
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Cloud Software Group | XenServer |
Affected:
all
(custom)
|
||
Credits
{
"containers": {
"cna": {
"affected": [
{
"product": "XenServer",
"vendor": "Cloud Software Group",
"versions": [
{
"status": "affected",
"version": "all",
"versionType": "custom"
}
]
},
{
"product": "XCP-ng",
"vendor": "Vates",
"versions": [
{
"status": "affected",
"version": "all",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Jakob Wolffhechel, Moksha"
}
],
"descriptions": [
{
"lang": "en",
"value": "A vm-admin in XAPI-based hypervisors (XenServer, XCP-ng) can disable NIC offload features (TSO, GSO, etc.) on VIF backend devices by setting ethtool-tso=off and similar keys in VIF.other_config. The VIF hotplug script (vif-real:85-97) executes ethtool -K to disable offloads. This forces host CPU to perform software segmentation, increasing CPU utilization and degrading performance for co-located VMs. VIF.other_config has zero map_keys_roles entries - all ethtool keys are writable by vm-admin."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 4.3,
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
"version": "3.1"
},
"format": "CVSS"
},
{
"cvssV4_0": {
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
"version": "4.0"
},
"format": "CVSS"
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-862",
"description": "Missing Authorization",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-04-24T06:00:00Z",
"orgId": "moksha.dk",
"shortName": "Moksha"
},
"references": [
{
"url": "https://cna.moksha.dk/MOKSHA-2026-0077"
}
],
"title": "VIF NIC Offload Disablement via VIF.other_config ethtool Keys"
}
},
"cveMetadata": {
"alternateIds": [
"GCVE-117-2026-0077"
],
"assignerOrgId": "moksha.dk",
"cveId": "MOKSHA-2026-0077",
"datePublished": "2026-04-24T06:00:00Z",
"state": "PUBLISHED",
"x_moksha_note": "Self-issued advisory. MOKSHA-2026-NNNN is not a MITRE CVE ID. Schema follows CVE JSON 5.1 for tooling compatibility. alternateIds contains GCVE cross-references (GNA #117) and will also carry MITRE CVE IDs if assigned."
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1"
}
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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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