CVE-2026-49429 (GCVE-0-2026-49429)
Vulnerability from cvelistv5 – Published: 2026-08-19 05:15 – Updated: 2026-08-20 03:55
VLAI
EPSS
VEX
Title
Kernel heap overflow in ZFS_IOC_USERSPACE_MANY ioctl
Summary
The ZFS_IOC_USERSPACE_MANY ioctl, used by zfs-userspace(8), truncated a 64-bit output buffer size to a 32-bit integer for the kernel allocation, but used the original 64-bit size as the buffer limit when writing records.
A local user with the "userused" delegated ZFS permission can trigger a kernel heap overflow via the ZFS_IOC_USERSPACE_MANY ioctl, potentially escalating privileges.
Severity
7.8 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-19 00:00 UTC
CWE
- CWE-122 - Heap-based Buffer Overflow
Assigner
freebsd
CNA
References
1 reference
| URL | Tags |
|---|---|
| https://security.freebsd.org/advisories/FreeBSD-S… | vendor-advisory |
Impacted products
Date Public
2026-06-30 20:00
{
"containers": {
"adp": [
{
"metrics": [
{
"cvssV3_1": {
"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"
}
},
{
"other": {
"content": {
"id": "CVE-2026-49429",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-19T00:00:00+00:00",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-08-20T03:55:49.215Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unknown",
"modules": [
"zfs"
],
"product": "FreeBSD",
"vendor": "FreeBSD",
"versions": [
{
"lessThan": "p1",
"status": "affected",
"version": "15.1-RELEASE",
"versionType": "release"
},
{
"lessThan": "p11",
"status": "affected",
"version": "15.0-RELEASE",
"versionType": "release"
},
{
"lessThan": "p7",
"status": "affected",
"version": "14.4-RELEASE",
"versionType": "release"
},
{
"lessThan": "p16",
"status": "affected",
"version": "14.3-RELEASE",
"versionType": "release"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai"
},
{
"lang": "en",
"type": "finder",
"value": "Emmanuel Genier at Quarkslab"
}
],
"datePublic": "2026-06-30T20:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "The ZFS_IOC_USERSPACE_MANY ioctl, used by zfs-userspace(8), truncated a 64-bit output buffer size to a 32-bit integer for the kernel allocation, but used the original 64-bit size as the buffer limit when writing records.\n\nA local user with the \"userused\" delegated ZFS permission can trigger a kernel heap overflow via the ZFS_IOC_USERSPACE_MANY ioctl, potentially escalating privileges."
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-122",
"description": "CWE-122: Heap-based Buffer Overflow",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T05:15:21.198Z",
"orgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
"shortName": "freebsd"
},
"references": [
{
"tags": [
"vendor-advisory"
],
"url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:40.zfs.asc"
}
],
"title": "Kernel heap overflow in ZFS_IOC_USERSPACE_MANY ioctl",
"x_generator": {
"engine": "cvelib 1.8.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
"assignerShortName": "freebsd",
"cveId": "CVE-2026-49429",
"datePublished": "2026-08-19T05:15:21.198Z",
"dateReserved": "2026-05-29T20:24:28.616Z",
"dateUpdated": "2026-08-20T03:55:49.215Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"vulnrichment": {
"containers": {
"adp": [
{
"metrics": [
{
"cvssV3_1": {
"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"
}
},
{
"other": {
"content": {
"id": "CVE-2026-49429",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-19T12:16:14.445112Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T12:16:32.478Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unknown",
"modules": [
"zfs"
],
"product": "FreeBSD",
"vendor": "FreeBSD",
"versions": [
{
"lessThan": "p1",
"status": "affected",
"version": "15.1-RELEASE",
"versionType": "release"
},
{
"lessThan": "p11",
"status": "affected",
"version": "15.0-RELEASE",
"versionType": "release"
},
{
"lessThan": "p7",
"status": "affected",
"version": "14.4-RELEASE",
"versionType": "release"
},
{
"lessThan": "p16",
"status": "affected",
"version": "14.3-RELEASE",
"versionType": "release"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai"
},
{
"lang": "en",
"type": "finder",
"value": "Emmanuel Genier at Quarkslab"
}
],
"datePublic": "2026-06-30T20:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "The ZFS_IOC_USERSPACE_MANY ioctl, used by zfs-userspace(8), truncated a 64-bit output buffer size to a 32-bit integer for the kernel allocation, but used the original 64-bit size as the buffer limit when writing records.\n\nA local user with the \"userused\" delegated ZFS permission can trigger a kernel heap overflow via the ZFS_IOC_USERSPACE_MANY ioctl, potentially escalating privileges."
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-122",
"description": "CWE-122: Heap-based Buffer Overflow",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T05:15:21.198Z",
"orgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
"shortName": "freebsd"
},
"references": [
{
"tags": [
"vendor-advisory"
],
"url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:40.zfs.asc"
}
],
"title": "Kernel heap overflow in ZFS_IOC_USERSPACE_MANY ioctl",
"x_generator": {
"engine": "cvelib 1.8.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
"assignerShortName": "freebsd",
"cveId": "CVE-2026-49429",
"datePublished": "2026-08-19T05:15:21.198Z",
"dateReserved": "2026-05-29T20:24:28.616Z",
"dateUpdated": "2026-08-20T03:55:49.215Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
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.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
Loading timeline…
Loading…
Loading…
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.
Loading…
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.