HighFix available
libcap2 — security advisory
A flaw was found in libcap. A local unprivileged user can exploit a Time-of-check-to-time-of-use (TOCTOU) race condition in the `cap_set_file()` function. This allows an attacker with write access to a parent directory to redirect file capability updates to an attacker-controlled file. By doing so, capabilities can be injected into or stripped from unintended executables, leading to privilege escalation.
- Products
- libcap2
- Affected versions
- 1:2.66-4, 1:2.66-4+deb12u1, 1:2.66-4+deb12u2, 1:2.75-10, 1:2.77-1
- Fixed versions
- 1:2.66-4+deb12u3, 1:2.75-10+deb13u1, 1:2.78-1
- CVEs
- CVE-2026-4878
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 17:41 UTC · Revision 1
Source evidence
A flaw was found in libcap. A local unprivileged user can exploit a Time-of-check-to-time-of-use (TOCTOU) race condition in the `cap_set_file()` function. This allows an attacker with write access to a parent directory to redirect file capability updates to an attacker-controlled file. By doing so, capabilities can be injected into or stripped from unintended executables, leading to privilege escalation.
osv:DEBIAN-CVE-2026-4878
libcap2
Fixed versions: 1:2.66-4+deb12u3
libcap2
Fixed versions: 1:2.75-10+deb13u1
libcap2
Fixed versions: 1:2.78-1
Complete source record
{
"id": "036d1528484663d3dca830eb98f532a0d76018565468fa01f9c4d9bbf4ad2b16",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-4878",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-4878",
"summary": "A flaw was found in libcap. A local unprivileged user can exploit a Time-of-check-to-time-of-use (TOCTOU) race condition in the `cap_set_file()` function. This allows an attacker with write access to a parent directory to redirect file capability updates to an attacker-controlled file. By doing so, capabilities can be injected into or stripped from unintended executables, leading to privilege escalation.",
"evidence": "osv:DEBIAN-CVE-2026-4878",
"products": [
{
"name": {
"value": "libcap2",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:2.66-4+deb12u3",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "1:2.66-4",
"evidence": "/affected/0/versions"
},
{
"value": "1:2.66-4+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "1:2.66-4+deb12u2",
"evidence": "/affected/0/versions"
}
]
},
{
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"prerequisites": [],
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],
"affected_versions": [
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}
]
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{
"name": {
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"evidence": "/affected/2/package/name"
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},
{
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}
]
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-4878",
"aliases": [
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],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:2.66-4+deb12u3"
}
]
}
],
"package": {
"name": "libcap2",
"purl": "pkg:deb/debian/libcap2?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1:2.66-4",
"1:2.66-4+deb12u1",
"1:2.66-4+deb12u2"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-4878.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
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"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
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{
"fixed": "1:2.75-10+deb13u1"
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}
],
"package": {
"name": "libcap2",
"purl": "pkg:deb/debian/libcap2?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1:2.75-10"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-4878.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
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},
{
"fixed": "1:2.78-1"
}
]
}
],
"package": {
"name": "libcap2",
"purl": "pkg:deb/debian/libcap2?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1:2.75-10",
"1:2.77-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-4878.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-27T09:47:31.804420924Z",
"provider": "osv",
"upstream": [
"CVE-2026-4878"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-4878"
]
},
"related_cves": [
{
"value": "CVE-2026-4878",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 460993,
"published_at": "2026-04-09T16:16:31.987+00:00"
}