CVE-2020-28049
An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that -...
An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.
- Record
CVE-2020-28049- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - CVSS 2.0
- 3.3 Low
AV:L/AC:M/Au:N/C:P/I:P/A:N - Weakness
- CWE-362
- Updated
- 2026-11-02
CVE List
An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.
- Record
CVE-2020-28049- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-362
- Updated
- 2026-11-02
EUVDEUVD-2020-20539
An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.
- Record
EUVD-2020-20539- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-q868-g69p-72cw
An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that -...
An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.
- Record
GHSA-q868-g69p-72cw- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-362
- Updated
- 2026-11-02
OSVALPINE-CVE-2020-28049
An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.
- Record
ALPINE-CVE-2020-28049- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-03
OSV
An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.
- Record
CVE-2020-28049- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
Show 6 moreShow less
OSVDEBIAN-CVE-2020-28049
An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.
- Record
DEBIAN-CVE-2020-28049- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2020-28049
An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.
- Record
UBUNTU-CVE-2020-28049- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
OSVMGASA-2020-0412 No score
Updated sddm package fixes a security vulnerability
Fabian Vogt discovered a flaw in sddm before 0.19.0. A local attacker can take advantage of a race condition when creating the Xauthority file to escalate privileges (CVE-2020-28049).
- Record
MGASA-2020-0412- Updated
- 2026-11-02
OSVopenSUSE-SU-2020:1870-1 No score
Security update for sddm
This update for sddm fixes the following issue:
- Fix X not having access control on startup (boo#1177201, CVE-2020-28049).
- Record
openSUSE-SU-2020:1870-1- Updated
- 2026-11-02
OSVopenSUSE-SU-2020:1899-1 No score
Security update for sddm
This update for sddm fixes the following issue:
- Fix X not having access control on startup (boo#1177201, CVE-2020-28049).
This update was imported from the openSUSE:Leap:15.2:Update update project.
- Record
openSUSE-SU-2020:1899-1- Updated
- 2026-11-02
OSVopenSUSE-SU-2024:11376-1 No score
sddm-0.19.0-4.2 on GA media
These are all security issues fixed in the sddm-0.19.0-4.2 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2024:11376-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
sddmAlpine:v3.13 |
before 0.19.0-r0 | 0.19.0-r0 |
sddmAlpine:v3.14 |
before 0.19.0-r0 | 0.19.0-r0 |
sddmAlpine:v3.15 |
before 0.19.0-r0 | 0.19.0-r0 |
sddmAlpine:v3.16 |
before 0.19.0-r0 | 0.19.0-r0 |
sddmAlpine:v3.17 |
before 0.19.0-r0 | 0.19.0-r0 |
sddmAlpine:v3.18 |
before 0.19.0-r0 | 0.19.0-r0 |
sddmAlpine:v3.19 |
before 0.19.0-r0 | 0.19.0-r0 |
sddmAlpine:v3.20 |
before 0.19.0-r0 | 0.19.0-r0 |
sddmAlpine:v3.21 |
before 0.19.0-r0 | 0.19.0-r0 |
sddmAlpine:v3.22 |
before 0.19.0-r0 | 0.19.0-r0 |
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| Package | Affected | Fixed |
|---|---|---|
sddmAlpine:v3.23 |
before 0.19.0-r0 | 0.19.0-r0 |
sddmAlpine:v3.24 |
before 0.19.0-r0 | 0.19.0-r0 |
sddmDebian:12 |
before 0.19.0-1 | 0.19.0-1 |
sddmDebian:13 |
before 0.19.0-1 | 0.19.0-1 |
sddmDebian:14 |
before 0.19.0-1 | 0.19.0-1 |
sddmDebian:9 |
before 0.14.0-4+deb9u2, plus listed versions 0.14.0-40.14.0-4+deb9u1 |
0.14.0-4+deb9u2 |
sddmDebian:10 |
before 0.18.0-1+deb10u1, plus listed versions 0.18.0-1 |
0.18.0-1+deb10u1 |
sddmMageia:7 |
before 0.18.1-3.1.mga7 | 0.18.1-3.1.mga7 |
sddmUbuntu:16.04:LTS |
All versions, plus listed versions 0.11.0-0ubuntu110.11.0-0ubuntu120.13.0-1ubuntu10.13.0-1ubuntu30.13.0-1ubuntu40.13.0-1ubuntu5 |
None known |
sddmUbuntu:18.04:LTS |
All versions, plus listed versions 0.14.0-4ubuntu10.14.0-4ubuntu20.17.0-1ubuntu10.17.0-1ubuntu20.17.0-1ubuntu3 Show 4 moreShow less0.17.0-1ubuntu40.17.0-1ubuntu50.17.0-1ubuntu60.17.0-1ubuntu7 |
None known |
sddmUbuntu:20.04:LTS |
All versions, plus listed versions 0.18.0-1ubuntu20.18.1-1ubuntu10.18.1-1ubuntu2 |
None known |
sddmopenSUSE:Leap 15.1 |
before 0.18.0-lp152.5.3.1 | 0.18.0-lp152.5.3.1 |
sddmopenSUSE:Leap 15.2 |
before 0.18.0-lp152.5.3.1 | 0.18.0-lp152.5.3.1 |
sddmSUSE:Package Hub 15 SP2 |
before 0.18.0-bp152.5.3.1 | 0.18.0-bp152.5.3.1 |
sddmopenSUSE:Tumbleweed From an advisory covering 2 CVEs |
before 0.19.0-4.2 | 0.19.0-4.2 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| affected, aliases, references | OSV | |
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-28049 is a medium vulnerability (CVSS 6.3) in Sddm Project Sddm, published November 4, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.42%, the 36th percentile. Fixed in sddm 0.19.0-r0.
References
github.com/sddm/sddm/releases
bugzilla.suse.com/show_bug.cgi?id=CVE-2020-28049
debian.org/security/2020/dsa-4783
lists.debian.org/debian-lts-announce/2020/11/msg00009.html
lists.opensuse.org/opensuse-security-announce/2020-11/msg00031.html
Show 19 moreShow less
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GT3EX5NSQJJAKY63ENSMEDX6NYZLYY3S
security.gentoo.org/glsa/202402-02
nvd.nist.gov/vuln/detail/CVE-2020-28049
security.alpinelinux.org/vuln/CVE-2020-28049
security-tracker.debian.org/tracker/CVE-2020-28049
advisories.mageia.org/MGASA-2020-0412.html
bugs.mageia.org/show_bug.cgi?id=27565
openwall.com/lists/oss-security/2020/11/04/2
ubuntu.com/security/CVE-2020-28049
cve.org/CVERecord?id=CVE-2020-28049
suse.com/security/cve/CVE-2020-28049