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Fencer Intel
medium 6.3

CVE-2020-28049 json

An issue was discovered in SDDM before 0.19.0.

published 6y ago modified 4mo ago also EUVD-2020-20539

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

Summary

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.

Patch / fix

  • sddm_project sddm 0.19.0
  • sddm Debian 14, Debian 13, Debian 12 0.19.0-1

debian advisories DEBIAN-CVE-2020-28049

  • sddm openSUSE Tumbleweed 0.19.0-4.2
  • sddm Package Hub 15 SP2 0.18.0-bp152.5.3.1
  • sddm openSUSE Leap 15.2, openSUSE Leap 15.1 0.18.0-lp152.5.3.1

opensuse advisories openSUSE-SU-2024:11376-1openSUSE-SU-2020:1899-1openSUSE-SU-2020:1870-1

  • sddm Alpine 3.24, Alpine 3.23, Alpine 3.22 +9 more 0.19.0-r0

alpine advisories ALPINE-CVE-2020-28049

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • sddm Arch Linux 0.19.0-1

arch linux advisories AVG-1266

Is CVE-2020-28049 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-28049 updated cvss 7.8

sddm: local privilege escalation due to race condition in creation of the Xauthority file

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2y ago

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugzilla.suse.com https://bugzilla.suse.com/show_bug.cgi?id=CVE-2020-28049 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
NVD 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
CNA 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
NVD 2.0 3.3 AV:L/AC:M/Au:N/C:P/I:P/A:N

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.