MOKSHA-2026-0039 (moksha-2026-0039)
Vulnerability from moksha – Published: 2026-04-24 06:00 – Updated:
VLAI
Title
Filesystem Layout Manipulation via SR.sm_config nosubdir/subdir
Summary
A pool-operator in XAPI-based hypervisors (XenServer, XCP-ng) can manipulate the filesystem layout of NFS and MooseFS storage repositories by modifying the nosubdir or subdir key in SR.sm_config after SR creation. Changing nosubdir causes the driver to look for VDIs in the wrong directory. All VDIs appear missing, causing VM boot failures and complete data inaccessibility for all VMs on the affected SR. The attack is reversible but causes service disruption.
Severity
References
1 reference
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| Cloud Software Group | XenServer |
Affected:
all
(custom)
|
|
| Vates | XCP-ng |
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 pool-operator in XAPI-based hypervisors (XenServer, XCP-ng) can manipulate the filesystem layout of NFS and MooseFS storage repositories by modifying the nosubdir or subdir key in SR.sm_config after SR creation. Changing nosubdir causes the driver to look for VDIs in the wrong directory. All VDIs appear missing, causing VM boot failures and complete data inaccessibility for all VMs on the affected SR. The attack is reversible but causes service disruption."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 6.5,
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"format": "CVSS"
},
{
"cvssV4_0": {
"baseScore": 7.0,
"baseSeverity": "HIGH",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:L/SC:N/SI:L/SA:N",
"version": "4.0"
},
"format": "CVSS"
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-862",
"description": "Missing Authorization",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-20",
"description": "Improper Input Validation",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-04-24T06:00:00Z",
"orgId": "moksha.dk",
"shortName": "Moksha"
},
"references": [
{
"url": "https://cna.moksha.dk/MOKSHA-2026-0039"
}
],
"title": "Filesystem Layout Manipulation via SR.sm_config nosubdir/subdir"
}
},
"cveMetadata": {
"alternateIds": [
"GCVE-117-2026-0039"
],
"assignerOrgId": "moksha.dk",
"cveId": "MOKSHA-2026-0039",
"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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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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