usn-8560-1
Vulnerability from osv_ubuntu
Published
2026-07-20 12:28
Modified
2026-07-20 12:28
Summary
libxfont vulnerabilities
Details
It was discovered that libXfont incorrectly handled scaling bitmap fonts, leading to a heap buffer overflow. An attacker able to access the X server could use this issue to cause libXfont to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-56001)
It was discovered that libXfont did not properly check glyph bounds when reading PCF fonts, leading to a heap buffer overflow. An authenticated X client could use this issue to cause libXfont to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-56002)
It was discovered that libXfont did not properly check the size of the property buffer when parsing PCF fonts, leading to a heap buffer overflow. An authenticated X client could use this issue to cause libXfont to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-56003)
References
{
"affected": [
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-56001",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56002",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56003",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:Pro:14.04:LTS"
}
},
"ecosystem_specific": {
"availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
"binaries": [
{
"binary_name": "libxfont1",
"binary_version": "1:1.4.7-1ubuntu0.4+esm2"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:14.04:LTS",
"name": "libxfont",
"purl": "pkg:deb/ubuntu/libxfont@1:1.4.7-1ubuntu0.4+esm2?arch=source\u0026distro=esm-infra-legacy/trusty"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.4.7-1ubuntu0.4+esm2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1:1.4.6-1",
"1:1.4.6-1ubuntu1",
"1:1.4.7-1",
"1:1.4.7-1ubuntu0.1",
"1:1.4.7-1ubuntu0.2",
"1:1.4.7-1ubuntu0.3",
"1:1.4.7-1ubuntu0.4"
]
},
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-56001",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56002",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56003",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:Pro:16.04:LTS"
}
},
"ecosystem_specific": {
"availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
"binaries": [
{
"binary_name": "libxfont1",
"binary_version": "1:1.5.1-1ubuntu0.16.04.4+esm2"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:16.04:LTS",
"name": "libxfont",
"purl": "pkg:deb/ubuntu/libxfont@1:1.5.1-1ubuntu0.16.04.4+esm2?arch=source\u0026distro=esm-infra-legacy/xenial"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.5.1-1ubuntu0.16.04.4+esm2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1:1.5.1-1",
"1:1.5.1-1ubuntu0.16.04.1",
"1:1.5.1-1ubuntu0.16.04.2",
"1:1.5.1-1ubuntu0.16.04.3",
"1:1.5.1-1ubuntu0.16.04.4"
]
},
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-56001",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56002",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56003",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:Pro:18.04:LTS"
}
},
"ecosystem_specific": {
"availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
"binaries": [
{
"binary_name": "libxfont2",
"binary_version": "1:2.0.3-1ubuntu0.1~esm2"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:18.04:LTS",
"name": "libxfont",
"purl": "pkg:deb/ubuntu/libxfont@1:2.0.3-1ubuntu0.1~esm2?arch=source\u0026distro=esm-infra/bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1:2.0.3-1ubuntu0.1~esm2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1:2.0.1-3ubuntu1",
"1:2.0.1-4",
"1:2.0.1-4ubuntu1",
"1:2.0.3-1"
]
},
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-56001",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56002",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56003",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:Pro:20.04:LTS"
}
},
"ecosystem_specific": {
"availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
"binaries": [
{
"binary_name": "libxfont2",
"binary_version": "1:2.0.3-1ubuntu0.20.04.1~esm2"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:20.04:LTS",
"name": "libxfont",
"purl": "pkg:deb/ubuntu/libxfont@1:2.0.3-1ubuntu0.20.04.1~esm2?arch=source\u0026distro=esm-infra/focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1:2.0.3-1ubuntu0.20.04.1~esm2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1:2.0.3-1"
]
},
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-56001",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56002",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56003",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:22.04:LTS"
}
},
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "libxfont2",
"binary_version": "1:2.0.5-1ubuntu0.2"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "libxfont",
"purl": "pkg:deb/ubuntu/libxfont@1:2.0.5-1ubuntu0.2?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1:2.0.5-1ubuntu0.2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1:2.0.4-1build3",
"1:2.0.5-1",
"1:2.0.5-1build1"
]
},
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-56001",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56002",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56003",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:24.04:LTS"
}
},
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "libxfont2",
"binary_version": "1:2.0.6-1+deb13u1build0.24.04.2"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "libxfont",
"purl": "pkg:deb/ubuntu/libxfont@1:2.0.6-1+deb13u1build0.24.04.2?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1:2.0.6-1+deb13u1build0.24.04.2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1:2.0.6-1",
"1:2.0.6-1build1"
]
},
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-56001",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56002",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-56003",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:26.04:LTS"
}
},
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "libxfont2",
"binary_version": "1:2.0.6-2ubuntu0.2"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "libxfont",
"purl": "pkg:deb/ubuntu/libxfont@1:2.0.6-2ubuntu0.2?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1:2.0.6-2ubuntu0.2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1:2.0.6-1build1",
"1:2.0.6-1build2",
"1:2.0.6-2"
]
}
],
"aliases": [],
"details": "It was discovered that libXfont incorrectly handled scaling bitmap\nfonts, leading to a heap buffer overflow. An attacker able to access\nthe X server could use this issue to cause libXfont to crash,\nresulting in a denial of service, or possibly execute arbitrary code.\n(CVE-2026-56001)\n\nIt was discovered that libXfont did not properly check glyph bounds\nwhen reading PCF fonts, leading to a heap buffer overflow. An\nauthenticated X client could use this issue to cause libXfont to\ncrash, resulting in a denial of service, or possibly execute arbitrary\ncode. (CVE-2026-56002)\n\nIt was discovered that libXfont did not properly check the size of the\nproperty buffer when parsing PCF fonts, leading to a heap buffer\noverflow. An authenticated X client could use this issue to cause\nlibXfont to crash, resulting in a denial of service, or possibly\nexecute arbitrary code. (CVE-2026-56003)",
"id": "USN-8560-1",
"modified": "2026-07-20T12:28:31Z",
"published": "2026-07-20T12:28:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://ubuntu.com/security/notices/USN-8560-1"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2017-16611"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-56001"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-56002"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-56003"
}
],
"related": [],
"schema_version": "1.7.0",
"summary": "libxfont vulnerabilities",
"upstream": [
"UBUNTU-CVE-2017-16611",
"UBUNTU-CVE-2026-56001",
"UBUNTU-CVE-2026-56002",
"UBUNTU-CVE-2026-56003"
]
}
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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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