Low
nix — security advisory
Nix is a package manager for Linux and other Unix systems. Prior to 2.35.0, a malicious derivation executed with the recursive-nix experimental feature can exploit a time-of-check/time-of-use race involving final symlink handling in the LocalStore restore path. The race can cause writeFile to follow a substituted final symlink when opening a path with O_TRUNC instead of enforcing FinalSymlink::DontFollow, allowing the Nix process or nix-daemon to create or truncate an empty file outside the build sandbox with the daemon user's permissions. The primitive does not provide arbitrary-content writes and requires winning the race. This issue is fixed in version 2.35.0.
- Products
- nix
- Affected versions
- 2.16.1+dfsg-3ubuntu1, 2.18.1+dfsg-1ubuntu1, 2.18.1+dfsg-1ubuntu2, 2.18.1+dfsg-1ubuntu4, 2.18.1+dfsg-1ubuntu5, 2.18.1+dfsg-1ubuntu5+esm2, 2.26.3+dfsg-1ubuntu4, 2.26.3+dfsg-1ubuntu5, 2.3.10+dfsg1-1, 2.3.10+dfsg1-1build1, 2.32.5+dfsg-1ubuntu3, 2.32.5+dfsg-2ubuntu1, 2.34.3+dfsg-1, 2.34.6+dfsg-1, 2.34.6+dfsg-1build1, 2.34.8+dfsg-1, 2.34.8+dfsg-1build1, 2.6.0+dfsg-2, 2.6.0+dfsg-3, 2.6.0+dfsg-3ubuntu0.1~esm1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-64846
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:12 UTC · Revision 1
Source evidence
Nix is a package manager for Linux and other Unix systems. Prior to 2.35.0, a malicious derivation executed with the recursive-nix experimental feature can exploit a time-of-check/time-of-use race involving final symlink handling in the LocalStore restore path. The race can cause writeFile to follow a substituted final symlink when opening a path with O_TRUNC instead of enforcing FinalSymlink::DontFollow, allowing the Nix process or nix-daemon to create or truncate an empty file outside the build sandbox with the daemon user's permissions. The primitive does not provide arbitrary-content writes and requires winning the race. This issue is fixed in version 2.35.0.
osv:UBUNTU-CVE-2026-64846
nix
Fixed versions: Not specified
nix
Fixed versions: Not specified
nix
Fixed versions: Not specified
nix
Fixed versions: Not specified
Complete source record
{
"id": "3c3944f88eb36dc8561e7fda649a8cec07da185095100766564399e6e373a86a",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-64846",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-64846",
"summary": "Nix is a package manager for Linux and other Unix systems. Prior to 2.35.0, a malicious derivation executed with the recursive-nix experimental feature can exploit a time-of-check/time-of-use race involving final symlink handling in the LocalStore restore path. The race can cause writeFile to follow a substituted final symlink when opening a path with O_TRUNC instead of enforcing FinalSymlink::DontFollow, allowing the Nix process or nix-daemon to create or truncate an empty file outside the build sandbox with the daemon user's permissions. The primitive does not provide arbitrary-content writes and requires winning the race. This issue is fixed in version 2.35.0.",
"evidence": "osv:UBUNTU-CVE-2026-64846",
"products": [
{
"name": {
"value": "nix",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.3.10+dfsg1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.3.10+dfsg1-1build1",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.0+dfsg-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.0+dfsg-3",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.0+dfsg-3ubuntu0.1~esm1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "nix",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.16.1+dfsg-3ubuntu1",
"evidence": "/affected/1/versions"
},
{
"value": "2.18.1+dfsg-1ubuntu1",
"evidence": "/affected/1/versions"
},
{
"value": "2.18.1+dfsg-1ubuntu2",
"evidence": "/affected/1/versions"
},
{
"value": "2.18.1+dfsg-1ubuntu4",
"evidence": "/affected/1/versions"
},
{
"value": "2.18.1+dfsg-1ubuntu5",
"evidence": "/affected/1/versions"
},
{
"value": "2.18.1+dfsg-1ubuntu5+esm2",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "nix",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.34.3+dfsg-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.34.6+dfsg-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.34.6+dfsg-1build1",
"evidence": "/affected/2/versions"
},
{
"value": "2.34.8+dfsg-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.34.8+dfsg-1build1",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "nix",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.26.3+dfsg-1ubuntu4",
"evidence": "/affected/3/versions"
},
{
"value": "2.26.3+dfsg-1ubuntu5",
"evidence": "/affected/3/versions"
},
{
"value": "2.32.5+dfsg-1ubuntu3",
"evidence": "/affected/3/versions"
},
{
"value": "2.32.5+dfsg-2ubuntu1",
"evidence": "/affected/3/versions"
},
{
"value": "2.34.3+dfsg-1",
"evidence": "/affected/3/versions"
}
]
}
],
"severity": "low",
"structured": {
"id": "UBUNTU-CVE-2026-64846",
"aliases": [
"UBUNTU-CVE-2026-64846"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nix",
"purl": "pkg:deb/ubuntu/nix?arch=source&distro=esm-apps%2Fjammy",
"ecosystem": "Ubuntu:Pro:22.04:LTS"
},
"versions": [
"2.3.10+dfsg1-1",
"2.3.10+dfsg1-1build1",
"2.6.0+dfsg-2",
"2.6.0+dfsg-3",
"2.6.0+dfsg-3ubuntu0.1~esm1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64846.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nix-bin",
"binary_version": "2.6.0+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "nix-setup-systemd",
"binary_version": "2.6.0+dfsg-3ubuntu0.1~esm1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nix",
"purl": "pkg:deb/ubuntu/nix?arch=source&distro=esm-apps%2Fnoble",
"ecosystem": "Ubuntu:Pro:24.04:LTS"
},
"versions": [
"2.16.1+dfsg-3ubuntu1",
"2.18.1+dfsg-1ubuntu1",
"2.18.1+dfsg-1ubuntu2",
"2.18.1+dfsg-1ubuntu4",
"2.18.1+dfsg-1ubuntu5",
"2.18.1+dfsg-1ubuntu5+esm2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64846.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nix-bin",
"binary_version": "2.18.1+dfsg-1ubuntu5+esm2"
},
{
"binary_name": "nix-setup-systemd",
"binary_version": "2.18.1+dfsg-1ubuntu5+esm2"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nix",
"purl": "pkg:deb/ubuntu/nix?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"2.34.3+dfsg-1",
"2.34.6+dfsg-1",
"2.34.6+dfsg-1build1",
"2.34.8+dfsg-1",
"2.34.8+dfsg-1build1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64846.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nix-bin",
"binary_version": "2.34.8+dfsg-1build1"
},
{
"binary_name": "nix-setup-systemd",
"binary_version": "2.34.8+dfsg-1build1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nix",
"purl": "pkg:deb/ubuntu/nix?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"2.26.3+dfsg-1ubuntu4",
"2.26.3+dfsg-1ubuntu5",
"2.32.5+dfsg-1ubuntu3",
"2.32.5+dfsg-2ubuntu1",
"2.34.3+dfsg-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64846.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nix-bin",
"binary_version": "2.34.3+dfsg-1"
},
{
"binary_name": "nix-setup-systemd",
"binary_version": "2.34.3+dfsg-1"
}
]
}
}
],
"modified": "2026-10-17T13:00:33.970395948Z",
"provider": "osv",
"upstream": [
"CVE-2026-64846"
],
"references": [
"https://ubuntu.com/security/CVE-2026-64846",
"https://www.cve.org/CVERecord?id=CVE-2026-64846"
]
},
"related_cves": [
{
"value": "CVE-2026-64846",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 360697,
"published_at": "2026-08-20T17:19:00+00:00"
}