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UBUNTU-CVE-2026-55999
Severity: highType: vulnerabilityCVE-2026-55999
Local attackers with a X connection able to provide PCX fonts to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a heap buffer overflow via SetFont due to missing glyph boundary checks.
EPSS 0.3%top 81%
UBUNTU-CVE-2026-55999
0
HighVulnerabilityCVE-2026-55999gcveosvubuntu-cve-2026-55999ubuntu-pro-14-04-ltsubuntu-pro-16-04-ltsubuntu-pro-18-04-ltsubuntu-pro-20-04-ltsubuntu-22-04-ltsubuntu-24-04-ltsubuntu-25-10ubuntu-26-04-lts
Published: 07/08/2026 (07/08/2026, 09:16:00 UTC)
Source: GCVE Database
Product: xorg-server
Description
Local attackers with a X connection able to provide PCX fonts to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a heap buffer overflow via SetFont due to missing glyph boundary checks.
CVSS v3.1
Score 8.5high
Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Affected software
xorg-server
pkg:deb/ubuntu/xorg-server@2:1.15.1-0ubuntu2.11+esm12?arch=source&distro=esm-infra-legacy/trustyAffected versions
=2:1.14.3-3ubuntu2=2:1.14.3-3ubuntu3=2:1.14.3-3ubuntu4=2:1.14.3-5ubuntu1=2:1.14.4-1ubuntu1=2:1.14.4-1ubuntu2=2:1.14.4.901-0ubuntu2=2:1.14.5-1ubuntu2=2:1.14.5-1ubuntu4=2:1.15.0-1ubuntu1=2:1.15.0-1ubuntu2=2:1.15.0-1ubuntu3=2:1.15.0-1ubuntu4=2:1.15.0-1ubuntu6=2:1.15.0-1ubuntu7=2:1.15.1-0ubuntu1=2:1.15.1-0ubuntu2=2:1.15.1-0ubuntu2.1=2:1.15.1-0ubuntu2.4=2:1.15.1-0ubuntu2.5=2:1.15.1-0ubuntu2.6=2:1.15.1-0ubuntu2.7=2:1.15.1-0ubuntu2.9=2:1.15.1-0ubuntu2.10=2:1.15.1-0ubuntu2.11=2:1.15.1-0ubuntu2.11+esm2=2:1.15.1-0ubuntu2.11+esm3=2:1.15.1-0ubuntu2.11+esm4=2:1.15.1-0ubuntu2.11+esm5=2:1.15.1-0ubuntu2.11+esm6=2:1.15.1-0ubuntu2.11+esm7=2:1.15.1-0ubuntu2.11+esm8=2:1.15.1-0ubuntu2.11+esm9=2:1.15.1-0ubuntu2.11+esm11=2:1.15.1-0ubuntu2.11+esm12
xorg-server
pkg:deb/ubuntu/xorg-server@2:1.18.4-0ubuntu0.12+esm18?arch=source&distro=esm-infra/xenialAffected versions
=2:1.17.2-1ubuntu9=2:1.17.2-1ubuntu10=2:1.17.3-2ubuntu1=2:1.17.3-2ubuntu2=2:1.17.3-2ubuntu3=2:1.17.3-2ubuntu4=2:1.18.1-1ubuntu3=2:1.18.1-1ubuntu4=2:1.18.3-1ubuntu1=2:1.18.3-1ubuntu2=2:1.18.3-1ubuntu2.2=2:1.18.3-1ubuntu2.3=2:1.18.4-0ubuntu0.1=2:1.18.4-0ubuntu0.2=2:1.18.4-0ubuntu0.3=2:1.18.4-0ubuntu0.4=2:1.18.4-0ubuntu0.6=2:1.18.4-0ubuntu0.7=2:1.18.4-0ubuntu0.8=2:1.18.4-0ubuntu0.9=2:1.18.4-0ubuntu0.10=2:1.18.4-0ubuntu0.11=2:1.18.4-0ubuntu0.12=2:1.18.4-0ubuntu0.12+esm1=2:1.18.4-0ubuntu0.12+esm2=2:1.18.4-0ubuntu0.12+esm4=2:1.18.4-0ubuntu0.12+esm5=2:1.18.4-0ubuntu0.12+esm6=2:1.18.4-0ubuntu0.12+esm8=2:1.18.4-0ubuntu0.12+esm9=2:1.18.4-0ubuntu0.12+esm10=2:1.18.4-0ubuntu0.12+esm12=2:1.18.4-0ubuntu0.12+esm13=2:1.18.4-0ubuntu0.12+esm14=2:1.18.4-0ubuntu0.12+esm15=2:1.18.4-0ubuntu0.12+esm16=2:1.18.4-0ubuntu0.12+esm17=2:1.18.4-0ubuntu0.12+esm18
xorg-server-hwe-16.04
pkg:deb/ubuntu/xorg-server-hwe-16.04@2:1.19.6-1ubuntu4.1~16.04.6+esm10?arch=source&distro=esm-infra/xenialAffected versions
=2:1.18.4-1ubuntu6.1~16.04.1=2:1.18.4-1ubuntu6.1~16.04.2=2:1.19.3-1ubuntu1~16.04.2=2:1.19.3-1ubuntu1~16.04.3=2:1.19.3-1ubuntu1~16.04.4=2:1.19.5-0ubuntu2~16.04.1=2:1.19.6-1ubuntu4~16.04.1=2:1.19.6-1ubuntu4.1~16.04.1=2:1.19.6-1ubuntu4.1~16.04.2=2:1.19.6-1ubuntu4.1~16.04.3=2:1.19.6-1ubuntu4.1~16.04.4=2:1.19.6-1ubuntu4.1~16.04.5=2:1.19.6-1ubuntu4.1~16.04.6=2:1.19.6-1ubuntu4.1~16.04.6+esm1=2:1.19.6-1ubuntu4.1~16.04.6+esm3=2:1.19.6-1ubuntu4.1~16.04.6+esm4=2:1.19.6-1ubuntu4.1~16.04.6+esm5=2:1.19.6-1ubuntu4.1~16.04.6+esm6=2:1.19.6-1ubuntu4.1~16.04.6+esm7=2:1.19.6-1ubuntu4.1~16.04.6+esm8=2:1.19.6-1ubuntu4.1~16.04.6+esm9=2:1.19.6-1ubuntu4.1~16.04.6+esm10
xorg-server
pkg:deb/ubuntu/xorg-server@2:1.19.6-1ubuntu4.15+esm13?arch=source&distro=esm-infra/bionicAffected versions
=2:1.19.5-0ubuntu2=2:1.19.6-1ubuntu1=2:1.19.6-1ubuntu2=2:1.19.6-1ubuntu3=2:1.19.6-1ubuntu4=2:1.19.6-1ubuntu4.1=2:1.19.6-1ubuntu4.2=2:1.19.6-1ubuntu4.3=2:1.19.6-1ubuntu4.4=2:1.19.6-1ubuntu4.5=2:1.19.6-1ubuntu4.6=2:1.19.6-1ubuntu4.7=2:1.19.6-1ubuntu4.8=2:1.19.6-1ubuntu4.9=2:1.19.6-1ubuntu4.10=2:1.19.6-1ubuntu4.11=2:1.19.6-1ubuntu4.12=2:1.19.6-1ubuntu4.13=2:1.19.6-1ubuntu4.14=2:1.19.6-1ubuntu4.15=2:1.19.6-1ubuntu4.15+esm1=2:1.19.6-1ubuntu4.15+esm3=2:1.19.6-1ubuntu4.15+esm4=2:1.19.6-1ubuntu4.15+esm5=2:1.19.6-1ubuntu4.15+esm7=2:1.19.6-1ubuntu4.15+esm8=2:1.19.6-1ubuntu4.15+esm9=2:1.19.6-1ubuntu4.15+esm10=2:1.19.6-1ubuntu4.15+esm11=2:1.19.6-1ubuntu4.15+esm12=2:1.19.6-1ubuntu4.15+esm13
xorg-server-hwe-18.04
pkg:deb/ubuntu/xorg-server-hwe-18.04@2:1.20.8-2ubuntu2.2~18.04.11+esm5?arch=source&distro=esm-infra/bionicAffected versions
=2:1.20.1-3ubuntu2.1~18.04.1=2:1.20.4-1ubuntu3~18.04.1=2:1.20.5+git20191008-0ubuntu1~18.04.1=2:1.20.8-2ubuntu2.1~18.04.1=2:1.20.8-2ubuntu2.2~18.04.1=2:1.20.8-2ubuntu2.2~18.04.2=2:1.20.8-2ubuntu2.2~18.04.3=2:1.20.8-2ubuntu2.2~18.04.4=2:1.20.8-2ubuntu2.2~18.04.5=2:1.20.8-2ubuntu2.2~18.04.6=2:1.20.8-2ubuntu2.2~18.04.7=2:1.20.8-2ubuntu2.2~18.04.8=2:1.20.8-2ubuntu2.2~18.04.9=2:1.20.8-2ubuntu2.2~18.04.10=2:1.20.8-2ubuntu2.2~18.04.11=2:1.20.8-2ubuntu2.2~18.04.11+esm1=2:1.20.8-2ubuntu2.2~18.04.11+esm2=2:1.20.8-2ubuntu2.2~18.04.11+esm3=2:1.20.8-2ubuntu2.2~18.04.11+esm4=2:1.20.8-2ubuntu2.2~18.04.11+esm5
xorg-server
pkg:deb/ubuntu/xorg-server@2:1.20.13-1ubuntu1~20.04.20+esm1?arch=source&distro=esm-infra/focalAffected versions
=2:1.20.5+git20191008-0ubuntu1=2:1.20.6-1ubuntu1=2:1.20.7-2ubuntu1=2:1.20.7-2ubuntu2=2:1.20.8-2ubuntu2=2:1.20.8-2ubuntu2.1=2:1.20.8-2ubuntu2.2=2:1.20.8-2ubuntu2.3=2:1.20.8-2ubuntu2.4=2:1.20.8-2ubuntu2.6=2:1.20.9-2ubuntu1.1~20.04.1=2:1.20.9-2ubuntu1.2~20.04.1=2:1.20.9-2ubuntu1.2~20.04.2=2:1.20.11-1ubuntu1~20.04.2=2:1.20.13-1ubuntu1~20.04.2=2:1.20.13-1ubuntu1~20.04.3=2:1.20.13-1ubuntu1~20.04.4=2:1.20.13-1ubuntu1~20.04.5=2:1.20.13-1ubuntu1~20.04.6=2:1.20.13-1ubuntu1~20.04.8=2:1.20.13-1ubuntu1~20.04.9=2:1.20.13-1ubuntu1~20.04.12=2:1.20.13-1ubuntu1~20.04.14=2:1.20.13-1ubuntu1~20.04.15=2:1.20.13-1ubuntu1~20.04.16=2:1.20.13-1ubuntu1~20.04.17=2:1.20.13-1ubuntu1~20.04.18=2:1.20.13-1ubuntu1~20.04.19=2:1.20.13-1ubuntu1~20.04.20=2:1.20.13-1ubuntu1~20.04.20+esm1
xorg-server
pkg:deb/ubuntu/xorg-server@2:21.1.4-2ubuntu1.7~22.04.16?arch=source&distro=jammyAffected versions
=2:1.20.13-1ubuntu1=2:1.20.13-1ubuntu2=2:1.20.14-1ubuntu1=2:21.1.3-2ubuntu2=2:21.1.3-2ubuntu2.1=2:21.1.3-2ubuntu2.2=2:21.1.3-2ubuntu2.3=2:21.1.3-2ubuntu2.4=2:21.1.3-2ubuntu2.5=2:21.1.3-2ubuntu2.6=2:21.1.3-2ubuntu2.7=2:21.1.3-2ubuntu2.8=2:21.1.3-2ubuntu2.9=2:21.1.4-2ubuntu1.7~22.04.1=2:21.1.4-2ubuntu1.7~22.04.2=2:21.1.4-2ubuntu1.7~22.04.5=2:21.1.4-2ubuntu1.7~22.04.7=2:21.1.4-2ubuntu1.7~22.04.8=2:21.1.4-2ubuntu1.7~22.04.9=2:21.1.4-2ubuntu1.7~22.04.10=2:21.1.4-2ubuntu1.7~22.04.11=2:21.1.4-2ubuntu1.7~22.04.12=2:21.1.4-2ubuntu1.7~22.04.13=2:21.1.4-2ubuntu1.7~22.04.14=2:21.1.4-2ubuntu1.7~22.04.15=2:21.1.4-2ubuntu1.7~22.04.16
xwayland
pkg:deb/ubuntu/xwayland@2:22.1.1-1ubuntu0.20?arch=source&distro=jammyAffected versions
=2:21.1.2-0ubuntu1=2:21.1.3-1=2:21.1.3-1ubuntu1=2:21.1.4-1=2:22.1.0-1=2:22.1.1-1=2:22.1.1-1ubuntu0.1=2:22.1.1-1ubuntu0.2=2:22.1.1-1ubuntu0.3=2:22.1.1-1ubuntu0.4=2:22.1.1-1ubuntu0.5=2:22.1.1-1ubuntu0.6=2:22.1.1-1ubuntu0.7=2:22.1.1-1ubuntu0.9=2:22.1.1-1ubuntu0.10=2:22.1.1-1ubuntu0.11=2:22.1.1-1ubuntu0.12=2:22.1.1-1ubuntu0.13=2:22.1.1-1ubuntu0.14=2:22.1.1-1ubuntu0.15=2:22.1.1-1ubuntu0.17=2:22.1.1-1ubuntu0.18=2:22.1.1-1ubuntu0.19=2:22.1.1-1ubuntu0.20
xorg-server
pkg:deb/ubuntu/xorg-server@2:21.1.12-1ubuntu1.6?arch=source&distro=nobleAffected versions
=2:21.1.7-3ubuntu2=2:21.1.7-3ubuntu2.1=2:21.1.10-1ubuntu1=2:21.1.11-2ubuntu1=2:21.1.12-1ubuntu1=2:21.1.12-1ubuntu1.1=2:21.1.12-1ubuntu1.2=2:21.1.12-1ubuntu1.3=2:21.1.12-1ubuntu1.4=2:21.1.12-1ubuntu1.5=2:21.1.12-1ubuntu1.6
xwayland
pkg:deb/ubuntu/xwayland@2:23.2.6-1ubuntu0.8?arch=source&distro=nobleAffected versions
=2:23.2.0-1=2:23.2.0-1ubuntu0.1=2:23.2.3-1=2:23.2.4-1=2:23.2.4-1build1=2:23.2.4-1build2=2:23.2.4-1build3=2:23.2.6-1=2:23.2.6-1ubuntu0.1=2:23.2.6-1ubuntu0.2=2:23.2.6-1ubuntu0.4=2:23.2.6-1ubuntu0.5=2:23.2.6-1ubuntu0.6=2:23.2.6-1ubuntu0.7=2:23.2.6-1ubuntu0.8
xorg-server
pkg:deb/ubuntu/xorg-server@2:21.1.18-1ubuntu1.1?arch=source&distro=questingAffected versions
=2:21.1.16-1ubuntu1=2:21.1.18-1ubuntu1=2:21.1.18-1ubuntu1.1
xwayland
pkg:deb/ubuntu/xwayland@2:24.1.6-1ubuntu1.1?arch=source&distro=questingAffected versions
=2:24.1.6-1=2:24.1.6-1ubuntu1=2:24.1.6-1ubuntu1.1
xorg-server
pkg:deb/ubuntu/xorg-server@2:21.1.22-1ubuntu1?arch=source&distro=resoluteAffected versions
=2:21.1.18-1ubuntu1=2:21.1.21-1ubuntu1=2:21.1.22-1ubuntu1
xwayland
pkg:deb/ubuntu/xwayland@2:24.1.10-1?arch=source&distro=resoluteAffected versions
=2:24.1.6-1ubuntu1=2:24.1.8-1=2:24.1.9-1=2:24.1.10-1
Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-55999
- Osv Schema Version
- 1.7.0
- Aliases
- []
- Ecosystems
- ["Ubuntu:Pro:14.04:LTS","Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:25.10","Ubuntu:26.04:LTS"]
- Database Specific Severity
- null
- Cvss Version
- 3.1
Threat ID: 6a58b47468715ace43d8d580
Added to database: 07/16/2026, 10:37:40 UTC
Last updated: 07/31/2026, 19:24:46 UTC
Views: 5
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