acl — security advisory
acl before version 2.4.0 contains a time-of-check to time-of-use (TOCTOU) race condition vulnerability that allows local attackers to escalate privileges by replacing a pathname component with a symbolic link between an lstat() check and subsequent symlink-following operations such as stat(), chown(), chmod(), acl_get_file(), and acl_set_file(). Attackers who control a pathname component can redirect file access control list operations to arbitrary files when getfacl, setfacl, or chacl is invoked by a privileged process over an attacker-controlled path, resulting in local privilege escalation.
- Products
- acl
- Affected versions
- 2.3.1-3, 2.3.1-4, 2.3.1-5, 2.3.1-6, 2.3.2-1, 2.3.2-2, 2.3.2-3, 2.4.0-1
- Fixed versions
- 2.4.0-1
- CVEs
- CVE-2026-54370
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 12:22 UTC · Revision 2
Source evidence
acl before version 2.4.0 contains a time-of-check to time-of-use (TOCTOU) race condition vulnerability that allows local attackers to escalate privileges by replacing a pathname component with a symbolic link between an lstat() check and subsequent symlink-following operations such as stat(), chown(), chmod(), acl_get_file(), and acl_set_file(). Attackers who control a pathname component can redirect file access control list operations to arbitrary files when getfacl, setfacl, or chacl is invoked by a privileged process over an attacker-controlled path, resulting in local privilege escalation.
osv:DEBIAN-CVE-2026-54370
acl
Fixed versions: Not specified
acl
Fixed versions: Not specified
acl
Fixed versions: 2.4.0-1
Complete source record
{
"id": "ab3f0dd2e50ec455377aa444a6d0915bbdfc44f079bc475510aaaad9e7a5bb3a",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-54370",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-54370",
"summary": "acl before version 2.4.0 contains a time-of-check to time-of-use (TOCTOU) race condition vulnerability that allows local attackers to escalate privileges by replacing a pathname component with a symbolic link between an lstat() check and subsequent symlink-following operations such as stat(), chown(), chmod(), acl_get_file(), and acl_set_file(). Attackers who control a pathname component can redirect file access control list operations to arbitrary files when getfacl, setfacl, or chacl is invoked by a privileged process over an attacker-controlled path, resulting in local privilege escalation.",
"evidence": "osv:DEBIAN-CVE-2026-54370",
"products": [
{
"name": {
"value": "acl",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.3.1-3",
"evidence": "/affected/0/versions"
},
{
"value": "2.3.1-4",
"evidence": "/affected/0/versions"
},
{
"value": "2.3.1-5",
"evidence": "/affected/0/versions"
},
{
"value": "2.3.1-6",
"evidence": "/affected/0/versions"
},
{
"value": "2.3.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.3.2-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.3.2-3",
"evidence": "/affected/0/versions"
},
{
"value": "2.4.0-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
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},
"prerequisites": [],
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"affected_versions": [
{
"value": "2.3.2-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.3.2-3",
"evidence": "/affected/1/versions"
},
{
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"evidence": "/affected/1/versions"
}
]
},
{
"name": {
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"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
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"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
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"evidence": "/affected/2/versions"
},
{
"value": "2.3.2-3",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-54370",
"aliases": [
"DEBIAN-CVE-2026-54370"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
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}
]
}
],
"package": {
"name": "acl",
"purl": "pkg:deb/debian/acl?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"2.3.1-3",
"2.3.1-4",
"2.3.1-5",
"2.3.1-6",
"2.3.2-1",
"2.3.2-2",
"2.3.2-3",
"2.4.0-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54370.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "acl",
"purl": "pkg:deb/debian/acl?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"2.3.2-2",
"2.3.2-3",
"2.4.0-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54370.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.4.0-1"
}
]
}
],
"package": {
"name": "acl",
"purl": "pkg:deb/debian/acl?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"2.3.2-2",
"2.3.2-3"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54370.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T11:47:35.593481196Z",
"provider": "osv",
"upstream": [
"CVE-2026-54370"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-54370"
]
},
"related_cves": [
{
"value": "CVE-2026-54370",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 450920,
"published_at": "2026-06-29T14:16:57.67+00:00"
}